expansion multiply (#334)

* expansion multiply

Author: Rubtsowa

dpnp/backend.pxd

@@ -233,7 +233,7 @@ cpdef dparray dpnp_divide(dparray array1, dparray array2)
 cpdef dparray dpnp_hypot(dparray array1, dparray array2)
 cpdef dparray dpnp_maximum(dparray array1, dparray array2)
 cpdef dparray dpnp_minimum(dparray array1, dparray array2)
-cpdef dparray dpnp_multiply(dparray array1, dparray array2)
+cpdef dparray dpnp_multiply(dparray array1, array2)
 cpdef dparray dpnp_negative(dparray array1)
 cpdef dparray dpnp_power(dparray array1, dparray array2)
 cpdef dparray dpnp_remainder(dparray array1, dparray array2)

dpnp/backend_mathematical.pyx

@@ -159,8 +159,61 @@ cpdef tuple dpnp_modf(dparray x1):
     return result1, result2
 
 
-cpdef dparray dpnp_multiply(dparray x1, dparray x2):
-    return call_fptr_2in_1out(DPNP_FN_MULTIPLY, x1, x2, x1.shape)
+cpdef dparray dpnp_multiply(dparray x1, x2):
+    x2_is_scalar = dpnp.isscalar(x2)
+
+    x1_dtype_ = x1.dtype
+    x2_dtype_ = type(x2) if x2_is_scalar else x2.dtype
+
+    types_map = {float: dpnp.float64, int: dpnp.int64}
+    x1_dtype = types_map.get(x1_dtype_, x1_dtype_)
+    x2_dtype = types_map.get(x2_dtype_, x2_dtype_)
+
+    if x1_dtype == dpnp.float64:
+        if x2_dtype == dpnp.float64:
+            res_type = dpnp.float64
+        elif x2_dtype == dpnp.float32:
+            res_type = dpnp.float64
+        elif x2_dtype == dpnp.int64:
+            res_type = dpnp.float64
+        elif x2_dtype == dpnp.int32:
+            res_type = dpnp.float64
+    elif x1_dtype == dpnp.float32:
+        if x2_dtype == dpnp.float64:
+            res_type = dpnp.float32
+        elif x2_dtype == dpnp.float32:
+            res_type = dpnp.float32
+        elif x2_dtype == dpnp.int64:
+            res_type = dpnp.float32
+        elif x2_dtype == dpnp.int32:
+            res_type = dpnp.float32
+    elif x1_dtype == dpnp.int64:
+        if x2_dtype == dpnp.float64:
+            res_type = dpnp.float64
+        elif x2_dtype == dpnp.float32:
+            res_type = dpnp.float32
+        elif x2_dtype == dpnp.int64:
+            res_type = dpnp.int64
+        elif x2_dtype == dpnp.int32:
+            res_type = dpnp.int64
+    elif x1_dtype == dpnp.int32:
+        if x2_dtype == dpnp.float64:
+            res_type = dpnp.float64
+        elif x2_dtype == dpnp.float32:
+            res_type = dpnp.float32
+        elif x2_dtype == dpnp.int64:
+            res_type = dpnp.int32
+        elif x2_dtype == dpnp.int32:
+            res_type = dpnp.int32
+
+    cdef dparray result = dparray(x1.shape, dtype=res_type)
+
+    if x2_is_scalar:
+        for i in range(result.size):
+            result[i] = x1[i] * x2
+        return result
+    else:
+        return call_fptr_2in_1out(DPNP_FN_MULTIPLY, x1, x2, x1.shape)
 
 
 cpdef dpnp_nanprod(dparray x1):

dpnp/dpnp_iface_mathematical.py

@@ -684,14 +684,19 @@ def multiply(x1, x2, **kwargs):
     is_x1_dparray = isinstance(x1, dparray)
     is_x2_dparray = isinstance(x2, dparray)
 
-    if (not use_origin_backend(x1) and is_x1_dparray and is_x2_dparray and not kwargs):
-        if (x1.size != x2.size):
-            checker_throw_value_error("multiply", "size", x1.size, x2.size)
+    is_x1_scalar = dpnp.isscalar(x1)
+    is_x2_scalar = dpnp.isscalar(x2)
 
-        if (x1.shape != x2.shape):
-            checker_throw_value_error("multiply", "shape", x1.shape, x2.shape)
+    if (not use_origin_backend(x1) and (is_x1_dparray or is_x1_scalar)) and \
+            (not use_origin_backend(x2) and (is_x2_dparray or is_x2_scalar)) and \
+            not (is_x1_scalar and is_x2_scalar) and not kwargs:
 
-        return dpnp_multiply(x1, x2)
+        if is_x1_scalar:
+            return dpnp_multiply(x2, x1)
+        else:
+            if is_x1_dparray and is_x2_dparray:
+                if (x1.size == x2.size) and (x1.shape == x2.shape):
+                    return dpnp_multiply(x1, x2)
 
     return call_origin(numpy.multiply, x1, x2, **kwargs)