1 files changed, 87 insertions, 0 deletions
diff --git a/src/biveval.cpp b/src/biveval.cpp
new file mode 100644
index 00000000..05e83e21
--- /dev/null
+++ b/src/biveval.cpp
@@ -0,0 +1,87 @@
+/* procedures for evaluating Tseries */
+# include "projects.h"
+# define NEAR_ONE	1.00001
+static double ceval(struct PW_COEF *C, int n, projUV w, projUV w2) {
+    double d=0, dd=0, vd, vdd, tmp, *c;
+    int j;
+
+    for (C += n ; n-- ; --C ) {
+        if ( (j = C->m) != 0) {
+            vd = vdd = 0.;
+            for (c = C->c + --j; j ; --j ) {
+                vd = w2.v * (tmp = vd) - vdd + *c--;
+                vdd = tmp;
+            }
+            d = w2.u * (tmp = d) - dd + w.v * vd - vdd + 0.5 * *c;
+        } else
+            d = w2.u * (tmp = d) - dd;
+        dd = tmp;
+    }
+    if ( (j = C->m) != 0 ) {
+        vd = vdd = 0.;
+        for (c = C->c + --j; j ; --j ) {
+            vd = w2.v * (tmp = vd) - vdd + *c--;
+            vdd = tmp;
+        }
+        return (w.u * d - dd + 0.5 * ( w.v * vd - vdd + 0.5 * *c ));
+    } else
+        return (w.u * d - dd);
+}
+
+projUV /* bivariate Chebyshev polynomial entry point */
+bcheval(projUV in, Tseries *T) {
+    projUV w2, w;
+    projUV out;
+    /* scale to +-1 */
+    w.u = ( in.u + in.u - T->a.u ) * T->b.u;
+    w.v = ( in.v + in.v - T->a.v ) * T->b.v;
+    if (fabs(w.u) > NEAR_ONE || fabs(w.v) > NEAR_ONE) {
+        out.u = out.v = HUGE_VAL;
+        pj_errno = PJD_ERR_TCHEBY_VAL_OUT_OF_RANGE;
+    } else { /* double evaluation */
+        w2.u = w.u + w.u;
+        w2.v = w.v + w.v;
+        out.u = ceval(T->cu, T->mu, w, w2);
+        out.v = ceval(T->cv, T->mv, w, w2);
+    }
+    return out;
+}
+
+projUV /* bivariate power polynomial entry point */
+bpseval(projUV in, Tseries *T) {
+    projUV out;
+    double *c, row;
+    int i, m;
+
+    out.u = out.v = 0.;
+    for (i = T->mu; i >= 0; --i) {
+        row = 0.;
+        if ((m = T->cu[i].m) != 0) {
+            c = T->cu[i].c + m;
+            while (m--)
+                row = *--c + in.v * row;
+        }
+        out.u = row + in.u * out.u;
+    }
+    for (i = T->mv; i >= 0; --i) {
+        row = 0.;
+        if ((m = T->cv[i].m) != 0) {
+            c = T->cv[i].c + m;
+            while (m--)
+                row = *--c + in.v * row;
+        }
+        out.v = row + in.u * out.v;
+    }
+    return out;
+}
+
+projUV /* general entry point selecting evaluation mode */
+biveval(projUV in, Tseries *T) {
+
+    if (T->power) {
+        return bpseval(in, T);
+    } else {
+        return bcheval(in, T);
+    }
+}
+