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Still not quite there...

master
Pete Shadbolt 10 years ago
parent
commit
818714ce51
2 changed files with 15 additions and 35 deletions
  1. +6
    -4
      run-tests.py
  2. +9
    -31
      src/permanent.c

+ 6
- 4
run-tests.py View File

@@ -3,10 +3,12 @@ import time
import multiprocessing as mp
import numpy as np
import lib
import time

dimension=8
real=np.random.uniform(0,1,(dimension, dimension))
imag=np.random.uniform(0,1,(dimension, dimension))
dimension=2
real=np.ones((dimension, dimension))
imag=np.ones((dimension, dimension))
submatrix=real+1j*imag
print submatrix

print "OUTPUT:", lib.permanent(submatrix)
p=lib.permanent(submatrix)

+ 9
- 31
src/permanent.c View File

@@ -7,8 +7,6 @@
#include <complex.h>

// Globals
PyArrayObject *submatrix;
int size;

// Boilerplate: Forward function declaration.
static PyObject *permanent(PyObject *self, PyObject *args);
@@ -34,13 +32,16 @@ PyMODINIT_FUNC initpermanent(void) {
// Ryser's algorithm takes exponential time
// The advantage over naive perm() only kicks in at around 6x6 matrices
// TODO: should take matrix as arg really, get rid of consts
static npy_complex64 perm_ryser(void) {
static npy_complex64 perm_ryser(PyArrayObject *submatrix) {
int size = (int) PyArray_DIM(submatrix, 0);
npy_complex64 p;
p.real=0; p.imag=0;
int i, j;
for (i = 0; i < size; ++i) {
for (j = 0; j < size; ++j) {
npy_complex64 q = SM(0,0);
npy_complex64 q = SM(i,j);
printf("real: %f\n", q.real);
printf("imag: %f\n", q.imag);
p.real += q.real;
p.imag += q.imag;
}
@@ -48,43 +49,20 @@ static npy_complex64 perm_ryser(void) {
return p;
}

void TODO(void) {
int n = size;
int i = 0; int z = 0; int y = 0;
npy_complex64 perm; perm.real=0; perm.imag=0;
npy_complex64 prod;
npy_complex64 sum; sum.real=0; sum.imag=0;
npy_complex64 element;
int exp=pow(2.0, n);

// Iterate over exponentially many index strings
for (i=0; i<exp; ++i) {
prod.real = 1; prod.imag=0;
for (y=0; y<n; ++y) { // Rows
sum.real = 0; sum.imag = 0;
for (z=0; z<n; ++z) { // Columns
if ((i & (1 << z)) > 0) { sum.real += SM(z,y).real; sum.imag += SM(z,y).imag; }
}
prod = prod*sum;
}
perm += parity(i) * prod;
}
return (pow(-1,n))*perm;
}

// This is basically a wrapper which chooses the optimal permanent function
static PyObject *permanent(PyObject *self, PyObject *args) {
// Parse input
PyArrayObject *submatrix;
if (!PyArg_ParseTuple(args, "O!", &PyArray_Type, &submatrix)) {
return NULL;
}

// Check for stupid mistakes
if ((int) PyArray_NDIM(submatrix) != 2) {return NULL;}
size = (int) PyArray_DIM(submatrix, 0);
int size = (int) PyArray_DIM(submatrix, 0);
if ((int) PyArray_DIM(submatrix, 1) != size) {return NULL;}

// Get the permanent, convert to a python object, and return
npy_complex64 p = perm_ryser();
return PyComplex_FromDoubles(p.real,p.imag);
npy_complex64 p = perm_ryser(submatrix);
return PyComplex_FromDoubles(p.real, p.imag);
}

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