Merge pull request #617 from jepler/sinc-function

ulab.numpy: implement sinc for creating audio filters

Author: jepler

code/numpy/numpy.c

@@ -340,6 +340,9 @@ static const mp_rom_map_elem_t ulab_numpy_globals_table[] = {
     #if ULAB_NUMPY_HAS_SIN
     { MP_ROM_QSTR(MP_QSTR_sin), MP_ROM_PTR(&vector_sin_obj) },
     #endif
+    #if ULAB_NUMPY_HAS_SINC
+    { MP_ROM_QSTR(MP_QSTR_sinc), MP_ROM_PTR(&vector_sinc_obj) },
+    #endif
     #if ULAB_NUMPY_HAS_SINH
     { MP_ROM_QSTR(MP_QSTR_sinh), MP_ROM_PTR(&vector_sinh_obj) },
     #endif

code/numpy/vector.c

@@ -570,6 +570,27 @@ MATH_FUN_1(sin, sin);
 MP_DEFINE_CONST_FUN_OBJ_1(vector_sin_obj, vector_sin);
 #endif
 
+#if ULAB_NUMPY_HAS_SINC
+//| def sinc(a: _ArrayLike) -> ulab.numpy.ndarray:
+//|    """Computes the normalized sinc function"""
+//|    ...
+//|
+
+static mp_float_t ulab_sinc1(mp_float_t x) {
+    if (fpclassify(x) == FP_ZERO) {
+        return MICROPY_FLOAT_CONST(1.);
+    }
+    x *= MP_PI;
+    return MICROPY_FLOAT_C_FUN(sin)(x) / x;
+}
+
+static mp_obj_t vector_sinc(mp_obj_t x_obj) {
+    return vector_generic_vector(x_obj, ulab_sinc1);
+}
+
+MP_DEFINE_CONST_FUN_OBJ_1(vector_sinc_obj, vector_sinc);
+#endif
+
 #if ULAB_NUMPY_HAS_SINH
 //| def sinh(a: _ArrayLike) -> ulab.numpy.ndarray:
 //|    """Computes the hyperbolic sine"""

code/numpy/vector.h

@@ -39,6 +39,7 @@ MP_DECLARE_CONST_FUN_OBJ_1(vector_log10_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(vector_log2_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(vector_radians_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(vector_sin_obj);
+MP_DECLARE_CONST_FUN_OBJ_1(vector_sinc_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(vector_sinh_obj);
 #if ULAB_SUPPORTS_COMPLEX
 MP_DECLARE_CONST_FUN_OBJ_KW(vector_sqrt_obj);

code/ulab.h

@@ -616,6 +616,10 @@
 #define ULAB_NUMPY_HAS_SIN              (1)
 #endif
 
+#ifndef ULAB_NUMPY_HAS_SINC
+#define ULAB_NUMPY_HAS_SINC             (1)
+#endif
+
 #ifndef ULAB_NUMPY_HAS_SINH
 #define ULAB_NUMPY_HAS_SINH             (1)
 #endif

requirements_cp_dev.txt

@@ -15,5 +15,4 @@ myst-parser
 
 # For stubs and annotations
 adafruit-circuitpython-typing
-
-
+build