ode/src/fastltsolve.c
changeset 0 2f259fa3e83a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ode/src/fastltsolve.c	Tue Feb 02 01:00:49 2010 +0200
@@ -0,0 +1,198 @@
+/* generated code, do not edit. */
+
+#include <ode/matrix.h>
+
+/* solve L^T * x=b, with b containing 1 right hand side.
+ * L is an n*n lower triangular matrix with ones on the diagonal.
+ * L is stored by rows and its leading dimension is lskip.
+ * b is an n*1 matrix that contains the right hand side.
+ * b is overwritten with x.
+ * this processes blocks of 4.
+ */
+
+EXPORT_C void dSolveL1T (const dReal *L, dReal *B, int n, int lskip1)
+{  
+  /* declare variables - Z matrix, p and q vectors, etc */
+  dReal Z11,m11,Z21,m21,Z31,m31,Z41,m41,p1,q1,p2,p3,p4,*ex;
+  const dReal *ell;
+  int lskip2,i,j;
+  /* special handling for L and B because we're solving L1 *transpose* */
+  L = L + (n-1)*(lskip1+1);
+  B = B + n-1;
+  lskip1 = -lskip1;
+  /* compute lskip values */
+  lskip2 = 2*lskip1;
+  /* compute all 4 x 1 blocks of X */
+  for (i=0; i <= n-4; i+=4) {
+    /* compute all 4 x 1 block of X, from rows i..i+4-1 */
+    /* set the Z matrix to 0 */
+    Z11=0;
+    Z21=0;
+    Z31=0;
+    Z41=0;
+    ell = L - i;
+    ex = B;
+    /* the inner loop that computes outer products and adds them to Z */
+    for (j=i-4; j >= 0; j -= 4) {
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[0];
+      p2=ell[-1];
+      p3=ell[-2];
+      p4=ell[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      m21 = dMUL(p2,q1);
+      m31 = dMUL(p3,q1);
+      m41 = dMUL(p4,q1);
+      ell += lskip1;
+      Z11 += m11;
+      Z21 += m21;
+      Z31 += m31;
+      Z41 += m41;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-1];
+      p2=ell[-1];
+      p3=ell[-2];
+      p4=ell[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      m21 = dMUL(p2,q1);
+      m31 = dMUL(p3,q1);
+      m41 = dMUL(p4,q1);
+      ell += lskip1;
+      Z11 += m11;
+      Z21 += m21;
+      Z31 += m31;
+      Z41 += m41;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-2];
+      p2=ell[-1];
+      p3=ell[-2];
+      p4=ell[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      m21 = dMUL(p2,q1);
+      m31 = dMUL(p3,q1);
+      m41 = dMUL(p4,q1);
+      ell += lskip1;
+      Z11 += m11;
+      Z21 += m21;
+      Z31 += m31;
+      Z41 += m41;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-3];
+      p2=ell[-1];
+      p3=ell[-2];
+      p4=ell[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      m21 = dMUL(p2,q1);
+      m31 = dMUL(p3,q1);
+      m41 = dMUL(p4,q1);
+      ell += lskip1;
+      ex -= 4;
+      Z11 += m11;
+      Z21 += m21;
+      Z31 += m31;
+      Z41 += m41;
+      /* end of inner loop */
+    }
+    /* compute left-over iterations */
+    j += 4;
+    for (; j > 0; j--) {
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[0];
+      p2=ell[-1];
+      p3=ell[-2];
+      p4=ell[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      m21 = dMUL(p2,q1);
+      m31 = dMUL(p3,q1);
+      m41 = dMUL(p4,q1);
+      ell += lskip1;
+      ex -= 1;
+      Z11 += m11;
+      Z21 += m21;
+      Z31 += m31;
+      Z41 += m41;
+    }
+    /* finish computing the X(i) block */
+    Z11 = ex[0] - Z11;
+    ex[0] = Z11;
+    p1 = ell[-1];
+    Z21 = ex[-1] - Z21 - dMUL(p1,Z11);
+    ex[-1] = Z21;
+    p1 = ell[-2];
+    p2 = ell[-2+lskip1];
+    Z31 = ex[-2] - Z31 - dMUL(p1,Z11) - dMUL(p2,Z21);
+    ex[-2] = Z31;
+    p1 = ell[-3];
+    p2 = ell[-3+lskip1];
+    p3 = ell[-3+lskip2];
+    Z41 = ex[-3] - Z41 - dMUL(p1,Z11) - dMUL(p2,Z21) - dMUL(p3,Z31);
+    ex[-3] = Z41;
+    /* end of outer loop */
+  }
+  /* compute rows at end that are not a multiple of block size */
+  for (; i < n; i++) {
+    /* compute all 1 x 1 block of X, from rows i..i+1-1 */
+    /* set the Z matrix to 0 */
+    Z11=0;
+    ell = L - i;
+    ex = B;
+    /* the inner loop that computes outer products and adds them to Z */
+    for (j=i-4; j >= 0; j -= 4) {
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[0];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      ell += lskip1;
+      Z11 += m11;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-1];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      ell += lskip1;
+      Z11 += m11;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-2];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      ell += lskip1;
+      Z11 += m11;
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[-3];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      ell += lskip1;
+      ex -= 4;
+      Z11 += m11;
+      /* end of inner loop */
+    }
+    /* compute left-over iterations */
+    j += 4;
+    for (; j > 0; j--) {
+      /* load p and q values */
+      p1=ell[0];
+      q1=ex[0];
+      /* compute outer product and add it to the Z matrix */
+      m11 = dMUL(p1,q1);
+      ell += lskip1;
+      ex -= 1;
+      Z11 += m11;
+    }
+    /* finish computing the X(i) block */
+    Z11 = ex[0] - Z11;
+    ex[0] = Z11;
+  }
+}