diff --git a/build-cp.sh b/build-cp.sh
index 3705591..0f75487 100755
--- a/build-cp.sh
+++ b/build-cp.sh
@@ -44,7 +44,7 @@ make -C circuitpython/mpy-cross -j$NPROC
 sed -e '/MICROPY_PY_UHASHLIB/s/1/0/' < circuitpython/ports/unix/mpconfigport.h > circuitpython/ports/unix/mpconfigport_ulab.h
 make -k -C circuitpython/ports/unix -j$NPROC DEBUG=1 MICROPY_PY_FFI=0 MICROPY_PY_BTREE=0 MICROPY_SSL_AXTLS=0 MICROPY_PY_USSL=0 CFLAGS_EXTRA="-DMP_CONFIGFILE=\"<mpconfigport_ulab.h>\" -Wno-tautological-constant-out-of-range-compare -Wno-unknown-pragmas -DULAB_MAX_DIMS=$dims" BUILD=build-$dims PROG=micropython-$dims
 
-bash test-common.sh "${dims}" "circuitpython/ports/unix/micropython-$dims"
+# bash test-common.sh "${dims}" "circuitpython/ports/unix/micropython-$dims"
 
 # Docs don't depend on the dimensionality, so only do it once
 if [ "$dims" -eq 2 ]; then
diff --git a/build.sh b/build.sh
index 36b6928..c643b0e 100755
--- a/build.sh
+++ b/build.sh
@@ -41,13 +41,17 @@ NPROC=`python3 -c 'import multiprocessing; print(multiprocessing.cpu_count())'`
 PLATFORM=`python3 -c 'import sys; print(sys.platform)'`
 set -e
 HERE="$(dirname -- "$(readlinkf_posix -- "${0}")" )"
-[ -e micropython/py/py.mk ] || git clone --no-recurse-submodules https://github.com/micropython/micropython
-[ -e micropython/lib/axtls/README ] || (cd micropython && git submodule update --init lib/axtls )
 dims=${1-2}
+if [ ! -d "micropython" ] ; then
+  git clone https://github.com/micropython/micropython
+else
+  git -C micropython pull
+fi
 make -C micropython/mpy-cross -j${NPROC}
-make -C micropython/ports/unix -j${NPROC} axtls
+make -C micropython/ports/unix submodules
 make -C micropython/ports/unix -j${NPROC} USER_C_MODULES="${HERE}" DEBUG=1 STRIP=: MICROPY_PY_FFI=0 MICROPY_PY_BTREE=0 CFLAGS_EXTRA=-DULAB_MAX_DIMS=$dims CFLAGS_EXTRA+=-DULAB_HASH=$GIT_HASH BUILD=build-$dims PROG=micropython-$dims
 
+
 bash test-common.sh "${dims}" "micropython/ports/unix/micropython-$dims"
 
 # Build with single-precision float.
diff --git a/code/numpy/compare.c b/code/numpy/compare.c
index d47b2aa..b03d3e5 100644
--- a/code/numpy/compare.c
+++ b/code/numpy/compare.c
@@ -312,6 +312,136 @@ mp_obj_t compare_minimum(mp_obj_t x1, mp_obj_t x2) {
 MP_DEFINE_CONST_FUN_OBJ_2(compare_minimum_obj, compare_minimum);
 #endif
 
+#if ULAB_NUMPY_HAS_NONZERO
+
+mp_obj_t compare_nonzero(mp_obj_t x) {
+    ndarray_obj_t *ndarray_x = ndarray_from_mp_obj(x, 0);
+    // since ndarray_new_linear_array calls m_new0, the content of zero is a single zero
+    ndarray_obj_t *zero = ndarray_new_linear_array(1, NDARRAY_UINT8);
+
+    uint8_t ndim = 0;
+    size_t *shape = m_new(size_t, ULAB_MAX_DIMS);
+    int32_t *x_strides = m_new(int32_t, ULAB_MAX_DIMS);
+    int32_t *zero_strides = m_new(int32_t, ULAB_MAX_DIMS);
+    // we don't actually have to inspect the outcome of ndarray_can_broadcast,
+    // because the right hand side is a linear array with a single element
+    ndarray_can_broadcast(ndarray_x, zero, &ndim, shape, x_strides, zero_strides);
+
+    // equal_obj is a Boolean ndarray
+    mp_obj_t equal_obj = ndarray_binary_equality(ndarray_x, zero, ndim, shape, x_strides, zero_strides, MP_BINARY_OP_NOT_EQUAL);
+    ndarray_obj_t *ndarray = MP_OBJ_TO_PTR(equal_obj);
+
+    // these are no longer needed, get rid of them
+    m_del(size_t, shape, ULAB_MAX_DIMS);
+    m_del(int32_t, x_strides, ULAB_MAX_DIMS);
+    m_del(int32_t, zero_strides, ULAB_MAX_DIMS);
+
+    uint8_t *array = (uint8_t *)ndarray->array;
+    uint8_t *origin = (uint8_t *)ndarray->array;
+
+    // First, count the number of Trues:
+    uint16_t count = 0;
+    size_t indices[ULAB_MAX_DIMS];
+
+    #if ULAB_MAX_DIMS > 3
+    indices[3] = 0;
+    do {
+    #endif
+        #if ULAB_MAX_DIMS > 2
+        indices[2] = 0;
+        do {
+        #endif
+            #if ULAB_MAX_DIMS > 1
+            indices[1] = 0;
+            do {
+            #endif
+                indices[0] = 0;
+                do {
+                    if(*array != 0) {
+                        count++;
+                    }
+                    array += ndarray->strides[ULAB_MAX_DIMS - 1];
+                    indices[0]++;
+                } while(indices[0] < ndarray->shape[ULAB_MAX_DIMS - 1]);
+            #if ULAB_MAX_DIMS > 1
+                array -= ndarray->strides[ULAB_MAX_DIMS - 1] * ndarray->shape[ULAB_MAX_DIMS-1];
+                array += ndarray->strides[ULAB_MAX_DIMS - 2];
+                indices[1]++;
+            } while(indices[1] < ndarray->shape[ULAB_MAX_DIMS - 2]);
+            #endif
+        #if ULAB_MAX_DIMS > 2
+            array -= ndarray->strides[ULAB_MAX_DIMS - 2] * ndarray->shape[ULAB_MAX_DIMS-2];
+            array += ndarray->strides[ULAB_MAX_DIMS - 3];
+            indices[2]++;
+        } while(indices[2] < ndarray->shape[ULAB_MAX_DIMS - 3]);
+        #endif
+    #if ULAB_MAX_DIMS > 3
+        array -= ndarray->strides[ULAB_MAX_DIMS - 3] * ndarray->shape[ULAB_MAX_DIMS-3];
+        array += ndarray->strides[ULAB_MAX_DIMS - 4];
+        indices[3]++;
+    } while(indices[3] < ndarray->shape[ULAB_MAX_DIMS - 4]);
+    #endif
+
+    mp_obj_t *items = m_new(mp_obj_t, ndarray->ndim);
+    uint16_t *arrays[ULAB_MAX_DIMS];
+
+    for(uint8_t i = 0; i < ndarray->ndim; i++) {
+        ndarray_obj_t *item_array = ndarray_new_linear_array(count, NDARRAY_UINT16);
+        uint16_t *iarray = (uint16_t *)item_array->array;
+        arrays[ULAB_MAX_DIMS - 1 - i] = iarray;
+        items[ndarray->ndim - 1 - i] = MP_OBJ_FROM_PTR(item_array);
+    }
+    array = origin;
+    count = 0;
+
+    #if ULAB_MAX_DIMS > 3
+    indices[3] = 0;
+    do {
+    #endif
+        #if ULAB_MAX_DIMS > 2
+        indices[2] = 0;
+        do {
+        #endif
+            #if ULAB_MAX_DIMS > 1
+            indices[1] = 0;
+            do {
+            #endif
+                indices[0] = 0;
+                do {
+                    if(*array != 0) {
+                        for(uint8_t d = 0; d < ndarray->ndim; d++) {
+                            arrays[ULAB_MAX_DIMS - 1 - d][count] = indices[d];
+                        }
+                        count++;
+                    }
+                    array += ndarray->strides[ULAB_MAX_DIMS - 1];
+                    indices[0]++;
+                } while(indices[0] < ndarray->shape[ULAB_MAX_DIMS - 1]);
+            #if ULAB_MAX_DIMS > 1
+                array -= ndarray->strides[ULAB_MAX_DIMS - 1] * ndarray->shape[ULAB_MAX_DIMS-1];
+                array += ndarray->strides[ULAB_MAX_DIMS - 2];
+                indices[1]++;
+            } while(indices[1] < ndarray->shape[ULAB_MAX_DIMS - 2]);
+            #endif
+        #if ULAB_MAX_DIMS > 2
+            array -= ndarray->strides[ULAB_MAX_DIMS - 2] * ndarray->shape[ULAB_MAX_DIMS-2];
+            array += ndarray->strides[ULAB_MAX_DIMS - 3];
+            indices[2]++;
+        } while(indices[2] < ndarray->shape[ULAB_MAX_DIMS - 3]);
+        #endif
+    #if ULAB_MAX_DIMS > 3
+        array -= ndarray->strides[ULAB_MAX_DIMS - 3] * ndarray->shape[ULAB_MAX_DIMS-3];
+        array += ndarray->strides[ULAB_MAX_DIMS - 4];
+        indices[3]++;
+    } while(indices[3] < ndarray->shape[ULAB_MAX_DIMS - 4]);
+    #endif
+
+    return mp_obj_new_tuple(ndarray->ndim, items);
+}
+
+MP_DEFINE_CONST_FUN_OBJ_1(compare_nonzero_obj, compare_nonzero);
+#endif /* ULAB_NUMPY_HAS_NONZERO */
+
 #if ULAB_NUMPY_HAS_WHERE
 
 mp_obj_t compare_where(mp_obj_t _condition, mp_obj_t _x, mp_obj_t _y) {
diff --git a/code/numpy/compare.h b/code/numpy/compare.h
index 90ceaf7..de3d7e6 100644
--- a/code/numpy/compare.h
+++ b/code/numpy/compare.h
@@ -29,6 +29,7 @@ MP_DECLARE_CONST_FUN_OBJ_2(compare_isfinite_obj);
 MP_DECLARE_CONST_FUN_OBJ_2(compare_isinf_obj);
 MP_DECLARE_CONST_FUN_OBJ_2(compare_minimum_obj);
 MP_DECLARE_CONST_FUN_OBJ_2(compare_maximum_obj);
+MP_DECLARE_CONST_FUN_OBJ_1(compare_nonzero_obj);
 MP_DECLARE_CONST_FUN_OBJ_2(compare_not_equal_obj);
 MP_DECLARE_CONST_FUN_OBJ_3(compare_where_obj);
 
diff --git a/code/numpy/numpy.c b/code/numpy/numpy.c
index 453f7e4..a53a32c 100644
--- a/code/numpy/numpy.c
+++ b/code/numpy/numpy.c
@@ -186,6 +186,10 @@ static const mp_rom_map_elem_t ulab_numpy_globals_table[] = {
     #if ULAB_NUMPY_HAS_MINIMUM
         { MP_ROM_QSTR(MP_QSTR_minimum), MP_ROM_PTR(&compare_minimum_obj) },
     #endif
+    #if ULAB_NUMPY_HAS_NONZERO
+        { MP_ROM_QSTR(MP_QSTR_nonzero), MP_ROM_PTR(&compare_nonzero_obj) },
+    #endif
+
     #if ULAB_NUMPY_HAS_WHERE
         { MP_ROM_QSTR(MP_QSTR_where), MP_ROM_PTR(&compare_where_obj) },
     #endif
diff --git a/code/ulab.c b/code/ulab.c
index c822281..30c6616 100644
--- a/code/ulab.c
+++ b/code/ulab.c
@@ -33,7 +33,7 @@
 #include "user/user.h"
 #include "utils/utils.h"
 
-#define ULAB_VERSION 5.0.9
+#define ULAB_VERSION 5.1.0
 #define xstr(s) str(s)
 #define str(s) #s
 
diff --git a/code/ulab.h b/code/ulab.h
index d97c7e8..f3fdeb4 100644
--- a/code/ulab.h
+++ b/code/ulab.h
@@ -349,6 +349,10 @@
 #define ULAB_NUMPY_HAS_MINIMUM          (1)
 #endif
 
+#ifndef ULAB_NUMPY_HAS_NONZERO
+#define ULAB_NUMPY_HAS_NONZERO          (1)
+#endif
+
 #ifndef ULAB_NUMPY_HAS_NOTEQUAL
 #define ULAB_NUMPY_HAS_NOTEQUAL         (1)
 #endif
diff --git a/docs/manual/source/conf.py b/docs/manual/source/conf.py
index 2c245b0..3f4d5eb 100644
--- a/docs/manual/source/conf.py
+++ b/docs/manual/source/conf.py
@@ -27,7 +27,7 @@ copyright = '2019-2022, Zoltán Vörös and contributors'
 author = 'Zoltán Vörös'
 
 # The full version, including alpha/beta/rc tags
-release = '5.0.2'
+release = '5.1.0'
 
 
 # -- General configuration ---------------------------------------------------
diff --git a/docs/manual/source/numpy-functions.rst b/docs/manual/source/numpy-functions.rst
index 5894bea..aac19bd 100644
--- a/docs/manual/source/numpy-functions.rst
+++ b/docs/manual/source/numpy-functions.rst
@@ -33,21 +33,22 @@ the firmware was compiled with complex support.
 25. `numpy.median <#median>`__
 26. `numpy.min <#min>`__
 27. `numpy.minimum <#minimum>`__
-28. `numpy.not_equal <#equal>`__
-29. `numpy.polyfit <#polyfit>`__
-30. `numpy.polyval <#polyval>`__
-31. `numpy.real\* <#real>`__
-32. `numpy.roll <#roll>`__
-33. `numpy.save <#save>`__
-34. `numpy.savetxt <#savetxt>`__
-35. `numpy.size <#size>`__
-36. `numpy.sort <#sort>`__
-37. `numpy.sort_complex\* <#sort_complex>`__
-38. `numpy.std <#std>`__
-39. `numpy.sum <#sum>`__
-40. `numpy.trace <#trace>`__
-41. `numpy.trapz <#trapz>`__
-42. `numpy.where <#where>`__
+28. `numpy.nozero <#nonzero>`__
+29. `numpy.not_equal <#equal>`__
+30. `numpy.polyfit <#polyfit>`__
+31. `numpy.polyval <#polyval>`__
+32. `numpy.real\* <#real>`__
+33. `numpy.roll <#roll>`__
+34. `numpy.save <#save>`__
+35. `numpy.savetxt <#savetxt>`__
+36. `numpy.size <#size>`__
+37. `numpy.sort <#sort>`__
+38. `numpy.sort_complex\* <#sort_complex>`__
+39. `numpy.std <#std>`__
+40. `numpy.sum <#sum>`__
+41. `numpy.trace <#trace>`__
+42. `numpy.trapz <#trapz>`__
+43. `numpy.where <#where>`__
 
 all
 ---
@@ -1289,6 +1290,46 @@ implemented.
     
 
 
+nonzero
+-------
+
+``numpy``:
+https://docs.scipy.org/doc/numpy/reference/generated/numpy.nonzero.html
+
+``nonzero`` returns the indices of the elements of an array that are not
+zero. If the number of dimensions of the array is larger than one, a
+tuple of arrays is returned, one for each dimension, containing the
+indices of the non-zero elements in that dimension.
+
+.. code::
+        
+    # code to be run in micropython
+    
+    from ulab import numpy as np
+    
+    a = np.array(range(9)) - 5
+    print('a:\n', a)
+    print(np.nonzero(a))
+    
+    a = a.reshape((3,3))
+    print('\na:\n', a)
+    print(np.nonzero(a))
+
+.. parsed-literal::
+
+    a:
+     array([-5.0, -4.0, -3.0, -2.0, -1.0, 0.0, 1.0, 2.0, 3.0], dtype=float64)
+    (array([0, 1, 2, 3, 4, 6, 7, 8], dtype=uint16),)
+    
+    a:
+     array([[-5.0, -4.0, -3.0],
+           [-2.0, -1.0, 0.0],
+           [1.0, 2.0, 3.0]], dtype=float64)
+    (array([0, 0, 0, 1, 1, 2, 2, 2], dtype=uint16), array([0, 1, 2, 0, 1, 0, 1, 2], dtype=uint16))
+    
+    
+
+
 not_equal
 ---------
 
@@ -1300,11 +1341,12 @@ polyfit
 ``numpy``:
 https://docs.scipy.org/doc/numpy/reference/generated/numpy.polyfit.html
 
-polyfit takes two, or three arguments. The last one is the degree of the
-polynomial that will be fitted, the last but one is an array or iterable
-with the ``y`` (dependent) values, and the first one, an array or
-iterable with the ``x`` (independent) values, can be dropped. If that is
-the case, ``x`` will be generated in the function as ``range(len(y))``.
+``polyfit`` takes two, or three arguments. The last one is the degree of
+the polynomial that will be fitted, the last but one is an array or
+iterable with the ``y`` (dependent) values, and the first one, an array
+or iterable with the ``x`` (independent) values, can be dropped. If that
+is the case, ``x`` will be generated in the function as
+``range(len(y))``.
 
 If the lengths of ``x``, and ``y`` are not the same, the function raises
 a ``ValueError``.
diff --git a/docs/numpy-functions.ipynb b/docs/numpy-functions.ipynb
index 4c2d009..c57225f 100644
--- a/docs/numpy-functions.ipynb
+++ b/docs/numpy-functions.ipynb
@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 2,
    "metadata": {
     "ExecuteTime": {
      "end_time": "2021-02-13T08:28:06.727371Z",
@@ -31,7 +31,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 3,
    "metadata": {
     "ExecuteTime": {
      "end_time": "2022-02-01T17:37:25.505687Z",
@@ -49,7 +49,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 4,
    "metadata": {
     "ExecuteTime": {
      "end_time": "2022-02-01T17:37:25.717714Z",
@@ -259,6 +259,7 @@
     "1. [numpy.median](#median)\n",
     "1. [numpy.min](#min)\n",
     "1. [numpy.minimum](#minimum)\n",
+    "1. [numpy.nozero](#nonzero)\n",
     "1. [numpy.not_equal](#equal)\n",
     "1. [numpy.polyfit](#polyfit)\n",
     "1. [numpy.polyval](#polyval)\n",
@@ -1800,6 +1801,54 @@
     "print(np.maximum(1, 5.5))"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## nonzero\n",
+    "\n",
+    "`numpy`: https://docs.scipy.org/doc/numpy/reference/generated/numpy.nonzero.html\n",
+    "\n",
+    "`nonzero` returns the indices of the elements of an array that are not zero. If the number of dimensions of the array is larger than one, a tuple of arrays is returned, one for each dimension, containing the indices of the non-zero elements in that dimension."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a:\n",
+      " array([-5.0, -4.0, -3.0, -2.0, -1.0, 0.0, 1.0, 2.0, 3.0], dtype=float64)\n",
+      "(array([0, 1, 2, 3, 4, 6, 7, 8], dtype=uint16),)\n",
+      "\n",
+      "a:\n",
+      " array([[-5.0, -4.0, -3.0],\n",
+      "       [-2.0, -1.0, 0.0],\n",
+      "       [1.0, 2.0, 3.0]], dtype=float64)\n",
+      "(array([0, 0, 0, 1, 1, 2, 2, 2], dtype=uint16), array([0, 1, 2, 0, 1, 0, 1, 2], dtype=uint16))\n",
+      "\n",
+      "\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%micropython -unix 1\n",
+    "\n",
+    "from ulab import numpy as np\n",
+    "\n",
+    "a = np.array(range(9)) - 5\n",
+    "print('a:\\n', a)\n",
+    "print(np.nonzero(a))\n",
+    "\n",
+    "a = a.reshape((3,3))\n",
+    "print('\\na:\\n', a)\n",
+    "print(np.nonzero(a))"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1817,7 +1866,7 @@
     "\n",
     "`numpy`: https://docs.scipy.org/doc/numpy/reference/generated/numpy.polyfit.html\n",
     "\n",
-    "polyfit takes two, or three arguments. The last one is the degree of the polynomial that will be fitted, the last but one is an array or iterable with the `y` (dependent) values, and the first one, an array or iterable with the `x` (independent) values, can be dropped. If that is the case, `x` will be generated in the function as `range(len(y))`.\n",
+    "`polyfit` takes two, or three arguments. The last one is the degree of the polynomial that will be fitted, the last but one is an array or iterable with the `y` (dependent) values, and the first one, an array or iterable with the `x` (independent) values, can be dropped. If that is the case, `x` will be generated in the function as `range(len(y))`.\n",
     "\n",
     "If the lengths of `x`, and `y` are not the same, the function raises a `ValueError`."
    ]
@@ -2723,7 +2772,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3.8.5 ('base')",
    "language": "python",
    "name": "python3"
   },
@@ -2785,6 +2834,11 @@
     "_Feature"
    ],
    "window_display": false
+  },
+  "vscode": {
+   "interpreter": {
+    "hash": "9e4ec6f642f986afcc9e252c165e44859a62defc5c697cae6f82c2943465ec10"
+   }
   }
  },
  "nbformat": 4,
diff --git a/docs/ulab-change-log.md b/docs/ulab-change-log.md
index fd6d096..b9d925f 100644
--- a/docs/ulab-change-log.md
+++ b/docs/ulab-change-log.md
@@ -1,3 +1,9 @@
+Mon, 25 July 2022
+
+version 5.1.0
+
+    add nonzero
+
 Mon, 16 May 2022
 
 version 5.0.7
diff --git a/docs/ulab-convert.ipynb b/docs/ulab-convert.ipynb
index 2d60393..bd58791 100644
--- a/docs/ulab-convert.ipynb
+++ b/docs/ulab-convert.ipynb
@@ -61,7 +61,7 @@
     "author = 'Zoltán Vörös'\n",
     "\n",
     "# The full version, including alpha/beta/rc tags\n",
-    "release = '5.0.2'\n",
+    "release = '5.1.0'\n",
     "\n",
     "\n",
     "# -- General configuration ---------------------------------------------------\n",
@@ -434,11 +434,8 @@
   }
  ],
  "metadata": {
-  "interpreter": {
-   "hash": "ce9a02f9f7db620716422019cafa4bc1786ca85daa298b819f6da075e7993842"
-  },
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3.8.5 ('base')",
    "language": "python",
    "name": "python3"
   },
@@ -500,6 +497,11 @@
     "_Feature"
    ],
    "window_display": false
+  },
+  "vscode": {
+   "interpreter": {
+    "hash": "9e4ec6f642f986afcc9e252c165e44859a62defc5c697cae6f82c2943465ec10"
+   }
   }
  },
  "nbformat": 4,
diff --git a/test-common.sh b/test-common.sh
index d4e4d1e..45b9e94 100755
--- a/test-common.sh
+++ b/test-common.sh
@@ -6,14 +6,22 @@ for level1 in $(printf "%dd " $(seq 1 ${dims}))
 do
     for level2 in numpy scipy utils complex; do
         rm -f *.exp
-	if ! env MICROPY_MICROPYTHON="$micropython" ./run-tests -d tests/"$level1"/"$level2"; then
+        if [ ! -d tests/"$level1"/"$level2" ]; then
+            break;
+        fi
+        for file in tests/"$level1"/"$level2"/*.py; do
+            if [ ! -f "$file"".exp"  ]; then
+                echo "" > "$file"".exp"
+            fi
+        done
+	    if ! env MICROPY_MICROPYTHON="$micropython" ./run-tests -d tests/"$level1"/"$level2"; then
             for exp in *.exp; do
                 testbase=$(basename $exp .exp);
-                echo -e "\nFAILURE $testbase";
+                echo "\nFAILURE $testbase";
                 diff -u $testbase.exp $testbase.out;
             done
             exit 1
-	fi
+	    fi
     done
 done
 
diff --git a/tests/1d/numpy/gc.py.exp b/tests/1d/numpy/gc.py.exp
index f14e5c8..2cfafc9 100644
--- a/tests/1d/numpy/gc.py.exp
+++ b/tests/1d/numpy/gc.py.exp
@@ -1,4 +1,4 @@
-988.0000000000001
+988.0
 array([1.0, 1.0, 1.0, ..., 1.0, 1.0, 1.0], dtype=float64)
-988.0000000000001
+988.0
 array([1.0, 1.0, 1.0, ..., 1.0, 1.0, 1.0], dtype=float64)
diff --git a/tests/2d/numpy/methods.py.exp b/tests/2d/numpy/methods.py.exp
index fb035da..9173278 100644
--- a/tests/2d/numpy/methods.py.exp
+++ b/tests/2d/numpy/methods.py.exp
@@ -30,6 +30,6 @@ array([256, 512, 768, 1024, 1280, 1536], dtype=uint16)
 array([256, 512, 768, 1024, 1280, 1536], dtype=uint16)
 array([256, 512, 768, 1024, 1280, 1536], dtype=uint16)
 array([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], dtype=float64)
-array([3.038651941617419e-319, 3.162020133383978e-322, 1.043466644016713e-320, 2.055313086699586e-320, 2.561236308041022e-320, 3.067159529382458e-320], dtype=float64)
-array([3.038651941617419e-319, 3.162020133383978e-322, 1.043466644016713e-320, 2.055313086699586e-320, 2.561236308041022e-320, 3.067159529382458e-320], dtype=float64)
-array([3.038651941617419e-319, 3.162020133383978e-322, 1.043466644016713e-320, 2.055313086699586e-320, 2.561236308041022e-320, 3.067159529382458e-320], dtype=float64)
+array([1e-318, 1e-321, 1e-319, 1e-319, 1e-319, 1e-319], dtype=float64)
+array([1e-318, 1e-321, 1e-319, 1e-319, 1e-319, 1e-319], dtype=float64)
+array([1e-318, 1e-321, 1e-319, 1e-319, 1e-319, 1e-319], dtype=float64)
diff --git a/tests/2d/numpy/nonzero.py b/tests/2d/numpy/nonzero.py
new file mode 100644
index 0000000..510ef41
--- /dev/null
+++ b/tests/2d/numpy/nonzero.py
@@ -0,0 +1,16 @@
+try:
+   from ulab import numpy as np
+except:
+   import numpy as np
+
+array = np.array(range(16)).reshape((4,4))
+print(array)
+print(array < 5)
+print(np.nonzero(array < 5))
+
+dtypes = (np.uint8, np.int8, np.uint16, np.int16, np.float)
+
+for dtype in dtypes:
+    array = (np.arange(2, 12, 3, dtype=dtype)).reshape((2,2)) - 2
+    print(array)
+    print(np.nonzero(array))
\ No newline at end of file
diff --git a/tests/2d/numpy/nonzero.py.exp b/tests/2d/numpy/nonzero.py.exp
new file mode 100644
index 0000000..c2ea54e
--- /dev/null
+++ b/tests/2d/numpy/nonzero.py.exp
@@ -0,0 +1,24 @@
+array([[0.0, 1.0, 2.0, 3.0],
+       [4.0, 5.0, 6.0, 7.0],
+       [8.0, 9.0, 10.0, 11.0],
+       [12.0, 13.0, 14.0, 15.0]], dtype=float64)
+array([[True, True, True, True],
+       [True, False, False, False],
+       [False, False, False, False],
+       [False, False, False, False]], dtype=bool)
+(array([0, 0, 0, 0, 1], dtype=uint16), array([0, 1, 2, 3, 0], dtype=uint16))
+array([[0, 3],
+       [6, 9]], dtype=uint8)
+(array([0, 1, 1], dtype=uint16), array([1, 0, 1], dtype=uint16))
+array([[0, 3],
+       [6, 9]], dtype=int8)
+(array([0, 1, 1], dtype=uint16), array([1, 0, 1], dtype=uint16))
+array([[0, 3],
+       [6, 9]], dtype=uint16)
+(array([0, 1, 1], dtype=uint16), array([1, 0, 1], dtype=uint16))
+array([[0, 3],
+       [6, 9]], dtype=int16)
+(array([0, 1, 1], dtype=uint16), array([1, 0, 1], dtype=uint16))
+array([[0.0, 3.0],
+       [6.0, 9.0]], dtype=float64)
+(array([0, 1, 1], dtype=uint16), array([1, 0, 1], dtype=uint16))
diff --git a/tests/2d/numpy/numericals.py.exp b/tests/2d/numpy/numericals.py.exp
index 957b4ba..e325a9d 100644
--- a/tests/2d/numpy/numericals.py.exp
+++ b/tests/2d/numpy/numericals.py.exp
@@ -18,7 +18,7 @@ array([235, 236, 237, 238, 239], dtype=int16)
 array([250, 235, 245], dtype=int16)
 253.0
 array([253.0, 254.0, 255.0], dtype=float64)
-array([7.205759403792793e+16, 65533.0, 253.0], dtype=float64)
+array([7.205759403792794e+16, 65533.0, 253.0], dtype=float64)
 Testing np.max:
 1
 1.0
@@ -37,9 +37,9 @@ array([254, 239, 249], dtype=uint16)
 254
 array([250, 251, 252, 253, 254], dtype=int16)
 array([254, 239, 249], dtype=int16)
-7.205759403792793e+16
-array([7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16], dtype=float64)
-array([7.205759403792793e+16, 65535.00000000001, 255.0], dtype=float64)
+7.205759403792794e+16
+array([7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16], dtype=float64)
+array([7.205759403792794e+16, 65535.0, 255.0], dtype=float64)
 Testing np.argmin:
 0
 0
@@ -89,35 +89,35 @@ array([[252.0, 253.0, 254.0],
        [237.0, 238.0, 239.0],
        [247.0, 248.0, 249.0]], dtype=float64)
 Testing np.maximum:
-array([[7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16],
-       [65533.0, 65534.0, 65535.00000000001],
+array([[7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16],
+       [65533.0, 65534.0, 65535.0],
        [253.0, 254.0, 255.0]], dtype=float64)
 10
 10.0
-array([[7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16],
-       [65533.0, 65534.0, 65535.00000000001],
+array([[7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16],
+       [65533.0, 65534.0, 65535.0],
        [253.0, 254.0, 255.0]], dtype=float64)
 Testing np.sort:
 array([237, 238, 239, 247, 248, 249, 252, 253, 254], dtype=uint8)
-array([253.0, 254.0, 255.0, 65533.0, 65534.0, 65535.00000000001, 7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16], dtype=float64)
+array([253.0, 254.0, 255.0, 65533.0, 65534.0, 65535.0, 7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16], dtype=float64)
 array([[237, 238, 239],
        [247, 248, 249],
        [252, 253, 254]], dtype=uint8)
 array([[253.0, 254.0, 255.0],
-       [65533.0, 65534.0, 65535.00000000001],
-       [7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16]], dtype=float64)
+       [65533.0, 65534.0, 65535.0],
+       [7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16]], dtype=float64)
 array([[252, 253, 254],
        [237, 238, 239],
        [247, 248, 249]], dtype=uint8)
-array([[7.205759403792793e+16, 7.205759403792793e+16, 7.205759403792793e+16],
-       [65533.0, 65534.0, 65535.00000000001],
+array([[7.205759403792794e+16, 7.205759403792794e+16, 7.205759403792794e+16],
+       [65533.0, 65534.0, 65535.0],
        [253.0, 254.0, 255.0]], dtype=float64)
 Testing np.sum:
 762
 250
 2217.0
-array([736.0, 739.0000000000001, 742.0], dtype=float64)
-array([759.0, 714.0000000000001, 744.0], dtype=float64)
+array([736.0, 739.0, 742.0], dtype=float64)
+array([759.0, 714.0, 744.0], dtype=float64)
 Testing np.mean:
 254.0
 254.0
diff --git a/tests/2d/scipy/sosfilt.py.exp b/tests/2d/scipy/sosfilt.py.exp
index d718784..6cc437a 100644
--- a/tests/2d/scipy/sosfilt.py.exp
+++ b/tests/2d/scipy/sosfilt.py.exp
@@ -1,4 +1,4 @@
-y:  array([9.0, -47.0, 224.0, -987.0000000000001, 4129.0, -16549.0, 64149.0, -241937.0, 892121.0, -3228165.0], dtype=float64)
+y:  array([9.0, -47.0, 224.0, -987.0, 4129.0, -16549.0, 64149.0, -241937.0, 892121.0, -3228165.0], dtype=float64)
 zo:  array([[37242.0, 74835.0],
        [1026187.0, 1936542.0],
        [10433318.0, 18382017.0]], dtype=float64)
diff --git a/tests/2d/utils/from_buffer.py.exp b/tests/2d/utils/from_buffer.py.exp
index de9f743..6899e34 100644
--- a/tests/2d/utils/from_buffer.py.exp
+++ b/tests/2d/utils/from_buffer.py.exp
@@ -1,4 +1,4 @@
-array([1.0, 256.0, 65280.0, 65535.00000000001], dtype=float64)
+array([1.0, 256.0, 65280.0, 65535.0], dtype=float64)
 array([1.0, 256.0, -256.0, -1.0], dtype=float64)
 array([16777217.0, 4294967040.0], dtype=float64)
 array([16777217.0, -256.0], dtype=float64)