From 5937d593cb1ed086236713db74828205b2002286 Mon Sep 17 00:00:00 2001
From: Tim Hochberg <tim_hochberg@local>
Date: Sun, 19 Feb 2006 13:57:36 +0000
Subject: Dispatch to reciprocal, ones_like, copy, sqrt, square inside
 array_power and array_inplace_power when power is a scalar in [-1, 0, 1, 0.5,
 1, 2]. Also, added the ufuncs reciprocal and ones_like.

---
 numpy/core/src/arrayobject.c | 109 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 92 insertions(+), 17 deletions(-)

(limited to 'numpy/core/src/arrayobject.c')

diff --git a/numpy/core/src/arrayobject.c b/numpy/core/src/arrayobject.c
index a90fb7cca..43c148548 100644
--- a/numpy/core/src/arrayobject.c
+++ b/numpy/core/src/arrayobject.c
@@ -2311,7 +2311,11 @@ typedef struct {
                 *multiply,
                 *divide,
                 *remainder,
-                *power,
+                *power,
+                *square,
+                *reciprocal,
+                *ones_like,
+                *copy,
 		*sqrt,
                 *negative,
                 *absolute,
@@ -2341,7 +2345,8 @@ typedef struct {
 static NumericOps n_ops = {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
                            NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
                            NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
-                           NULL, NULL, NULL, NULL, NULL};
+                           NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
+                           NULL};
 
 /* Dictionary can contain any of the numeric operations, by name. 
   Those not present will not be changed
@@ -2367,7 +2372,11 @@ PyArray_SetNumericOps(PyObject *dict)
         SET(multiply);
         SET(divide);
         SET(remainder);
-        SET(power);
+        SET(power);
+        SET(square);
+        SET(reciprocal);
+        SET(ones_like);
+        SET(copy);
 	SET(sqrt);
         SET(negative);
         SET(absolute);
@@ -2412,7 +2421,11 @@ PyArray_GetNumericOps(void)
         GET(multiply);
         GET(divide);
         GET(remainder);
-        GET(power);
+        GET(power);
+        GET(square);
+        GET(reciprocal);
+        GET(ones_like);
+        GET(copy);
 	GET(sqrt);
         GET(negative);
         GET(absolute);
@@ -2527,6 +2540,16 @@ PyArray_GenericInplaceBinaryFunction(PyArrayObject *m1,
         }
         return PyObject_CallFunction(op, "OOO", m1, m2, m1);
 }
+
+static PyObject *
+PyArray_GenericInplaceUnaryFunction(PyArrayObject *m1, PyObject *op) 
+{
+        if (op == NULL) {
+                Py_INCREF(Py_NotImplemented);
+                return Py_NotImplemented; 
+        }
+        return PyObject_CallFunction(op, "OO", m1, m1);
+}
 
 static PyObject *
 array_add(PyArrayObject *m1, PyObject *m2) 
@@ -2557,12 +2580,61 @@ array_remainder(PyArrayObject *m1, PyObject *m2)
 {
         return PyArray_GenericBinaryFunction(m1, m2, n_ops.remainder);
 }
-
-static PyObject *
-array_power(PyArrayObject *m1, PyObject *m2) 
-{
-        return PyArray_GenericBinaryFunction(m1, m2, n_ops.power);
-}
+
+
+static PyObject *array_float(PyArrayObject *v);
+
+
+static int
+array_power_is_scalar(PyObject *o2, longdouble* exp) 
+{
+    PyObject *temp;
+    const int optimize_fpexps = 1;
+    if (PyInt_Check(o2)) {
+        *exp = (longdouble)PyInt_AsLong(o2);
+        return 1;
+    }
+    if (optimize_fpexps && PyFloat_Check(o2)) {
+        *exp = PyFloat_AsDouble(o2);
+        return 1;
+    }
+    if (PyArray_CheckScalar(o2)) {
+        if (PyArray_ISINTEGER(o2) || (optimize_fpexps && PyArray_ISFLOAT(o2))) {
+            temp = array_float(o2);
+            if (temp != NULL) {
+                *exp = PyFloat_AsDouble(o2);
+                Py_DECREF(temp);
+                return 1;
+            }
+        }
+    }
+    return 0;
+}
+
+static PyObject *
+fast_scalar_power_op(PyArrayObject *a1, PyObject *o2) {
+    double exp;
+    if (PyArray_Check(a1) && (PyArray_ISFLOAT(a1) || PyArray_ISCOMPLEX(a1))) {
+        if (array_power_is_scalar(o2, &exp)) {
+            if (exp == -1.0) return n_ops.reciprocal;
+            if (exp ==  0.0) return n_ops.ones_like;
+            if (exp ==  0.5) return n_ops.sqrt;
+            if (exp ==  1.0) return n_ops.copy;
+            if (exp ==  2.0) return n_ops.square;
+        }
+    }
+    return NULL;
+}
+
+static PyObject *
+array_power(PyArrayObject *a1, PyObject *o2) 
+{
+    PyObject *fastop;
+    fastop = fast_scalar_power_op(a1, o2);
+    if (fastop) return PyArray_GenericUnaryFunction(a1, fastop);
+    return PyArray_GenericBinaryFunction(a1, o2, n_ops.power);
+}
+    
 
 static PyObject *
 array_negative(PyArrayObject *m1) 
@@ -2640,12 +2712,15 @@ static PyObject *
 array_inplace_remainder(PyArrayObject *m1, PyObject *m2) 
 {
         return PyArray_GenericInplaceBinaryFunction(m1, m2, n_ops.remainder);
-}
-
+}
+
 static PyObject *
-array_inplace_power(PyArrayObject *m1, PyObject *m2) 
-{
-        return PyArray_GenericInplaceBinaryFunction(m1, m2, n_ops.power);
+array_inplace_power(PyArrayObject *a1, PyObject *o2) 
+{
+    PyObject *fastop;
+    fastop = fast_scalar_power_op(a1, o2);
+    if (fastop) return PyArray_GenericInplaceUnaryFunction(a1, fastop);
+    return PyArray_GenericInplaceBinaryFunction(a1, o2, n_ops.power);
 }
 
 static PyObject *
@@ -2808,8 +2883,8 @@ array_float(PyArrayObject *v)
         pv = v->descr->f->getitem(v->data, v);
         if (pv == NULL) return NULL;
         if (pv->ob_type->tp_as_number == 0) {
-                PyErr_SetString(PyExc_TypeError, "cannot convert to an "\
-				"int; scalar object is not a number");
+                PyErr_SetString(PyExc_TypeError, "cannot convert to a "\
+				"float; scalar object is not a number");
                 Py_DECREF(pv);
                 return NULL;
         }
-- 
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