Changeset 806c18 in git for factory/cf_resultant.cc

Timestamp:

Nov 15, 2010, 4:34:57 PM (13 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'spielwiese', '91fdef05f09f54b8d58d92a472e9c4a43aa4656f')

Children:

7c3bca08c96331a56864c1d35b8c2e8ff2e0be89

Parents:

c840d97af622b4e4da8761738b540e21144f716b

Message:

format

git-svn-id: file:///usr/local/Singular/svn/trunk@13655 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• factory/cf_resultant.cc (modified) (6 diffs)

factory/cf_resultant.cc

@@ -48 +48 @@
     // some checks on triviality
     if ( f.isZero() || g.isZero() ) {
-        trivialResult[0] = 0;
-        return trivialResult;
+        trivialResult[0] = 0;
+        return trivialResult;
     }
 
     // make x main variable
     if ( f.mvar() > x || g.mvar() > x ) {
-        if ( f.mvar() > g.mvar() )
-            X = f.mvar();
-        else
-            X = g.mvar();
-        F = swapvar( f, X, x );
-        G = swapvar( g, X, x );
+        if ( f.mvar() > g.mvar() )
+            X = f.mvar();
+        else
+            X = g.mvar();
+        F = swapvar( f, X, x );
+        G = swapvar( g, X, x );
     }
     else {
-        X = x;
-        F = f;
-        G = g;
+        X = x;
+        F = f;
+        G = g;
     }
     // at this point, we have to calculate the sequence of F and
@@ -83 +83 @@
     // make sure that S[j+1] is regular and j < n
     if ( m == n && j > 0 ) {
-        S[j-1] = LC( S[j], X ) * psr( S[j+1], S[j], X );
-        j--;
+        S[j-1] = LC( S[j], X ) * psr( S[j+1], S[j], X );
+        j--;
     } else if ( m < n ) {
-        S[j-1] = LC( S[j], X ) * LC( S[j], X ) * S[j+1];
-        j--;
+        S[j-1] = LC( S[j], X ) * LC( S[j], X ) * S[j+1];
+        j--;
     } else if ( m > n && j > 0 ) {
-        // calculate first step
-        r = degree( S[j], X );
-        R = LC( S[j+1], X );
-
-        // if there was a gap calculate similar polynomial
-        if ( j > r && r >= 0 )
-            S[r] = power( LC( S[j], X ), j - r ) * S[j] * power( R, j - r );
-
-        if ( r > 0 ) {
-            // calculate remainder
-            S[r-1] = psr( S[j+1], S[j], X ) * power( -R, j - r );
-            j = r-1;
-        }
+        // calculate first step
+        r = degree( S[j], X );
+        R = LC( S[j+1], X );
+
+        // if there was a gap calculate similar polynomial
+        if ( j > r && r >= 0 )
+            S[r] = power( LC( S[j], X ), j - r ) * S[j] * power( R, j - r );
+
+        if ( r > 0 ) {
+            // calculate remainder
+            S[r-1] = psr( S[j+1], S[j], X ) * power( -R, j - r );
+            j = r-1;
+        }
     }
 
     while ( j > 0 ) {
-        // at this point, 0 < j < n and S[j+1] is regular
-        r = degree( S[j], X );
-        R = LC( S[j+1], X );
-        
-        // if there was a gap calculate similar polynomial
-        if ( j > r && r >= 0 )
-            S[r] = (power( LC( S[j], X ), j - r ) * S[j]) / power( R, j - r );
-
-        if ( r <= 0 ) break;
-        // calculate remainder
-        S[r-1] = psr( S[j+1], S[j], X ) / power( -R, j - r + 2 );
-
-        j = r-1;
-        // again 0 <= j < r <= jOld and S[j+1] is regular
+        // at this point, 0 < j < n and S[j+1] is regular
+        r = degree( S[j], X );
+        R = LC( S[j+1], X );
+
+        // if there was a gap calculate similar polynomial
+        if ( j > r && r >= 0 )
+            S[r] = (power( LC( S[j], X ), j - r ) * S[j]) / power( R, j - r );
+
+        if ( r <= 0 ) break;
+        // calculate remainder
+        S[r-1] = psr( S[j+1], S[j], X ) / power( -R, j - r + 2 );
+
+        j = r-1;
+        // again 0 <= j < r <= jOld and S[j+1] is regular
     }
 
     for ( j = 0; j <= S.max(); j++ ) {
-        // reswap variables if necessary
-        if ( X != x ) {
-            S[j] = swapvar( S[j], X, x );
-        }
+        // reswap variables if necessary
+        if ( X != x ) {
+            S[j] = swapvar( S[j], X, x );
+        }
     }
 
@@ -148 +148 @@
     // f or g in R
     if ( degree( f, x ) == 0 )
-        return power( f, degree( g, x ) );
+        return power( f, degree( g, x ) );
     if ( degree( g, x ) == 0 )
-        return power( g, degree( f, x ) );
+        return power( g, degree( f, x ) );
 
     // f and g are linear polynomials
@@ -180 +180 @@
     // here because this may involve variable swapping.
     if ( f.isZero() || g.isZero() )
-        return 0;
+        return 0;
     if ( f.mvar() < x )
-        return power( f, g.degree( x ) );
+        return power( f, g.degree( x ) );
     if ( g.mvar() < x )
-        return power( g, f.degree( x ) );
+        return power( g, f.degree( x ) );
 
     // make x main variale
@@ -190 +190 @@
     Variable X;
     if ( f.mvar() > x || g.mvar() > x ) {
-        if ( f.mvar() > g.mvar() )
-            X = f.mvar();
-        else
-            X = g.mvar();
-        F = swapvar( f, X, x );
-        G = swapvar( g, X, x );
+        if ( f.mvar() > g.mvar() )
+            X = f.mvar();
+        else
+            X = g.mvar();
+        F = swapvar( f, X, x );
+        G = swapvar( g, X, x );
     }
     else {
-        X = x;
-        F = f;
-        G = g;
+        X = x;
+        F = f;
+        G = g;
     }
     // at this point, we have to calculate resultant( F, G, X )
@@ -210 +210 @@
     // catch trivial cases
     if ( m+n <= 2 || m == 0 || n == 0 )
-        return swapvar( trivialResultant( F, G, X ), X, x );
+        return swapvar( trivialResultant( F, G, X ), X, x );
 
     // exchange F and G if necessary
     int flipFactor;
     if ( m < n ) {
-        CanonicalForm swap = F;
-        F = G; G = swap;
-        int degswap = m;
-        m = n; n = degswap;
-        if ( m & 1 && n & 1 )
-            flipFactor = -1;
-        else
-            flipFactor = 1;
+        CanonicalForm swap = F;
+        F = G; G = swap;
+        int degswap = m;
+        m = n; n = degswap;
+        if ( m & 1 && n & 1 )
+            flipFactor = -1;
+        else
+            flipFactor = 1;
     } else
-        flipFactor = 1;
+        flipFactor = 1;
 
     // this is not an effective way to calculate the resultant!
     CanonicalForm extFactor;
     if ( m == n ) {
-        if ( n & 1 )
-            extFactor = -LC( G, X );
-        else
-            extFactor = LC( G, X );
+        if ( n & 1 )
+            extFactor = -LC( G, X );
+        else
+            extFactor = LC( G, X );
     } else
-        extFactor = power( LC( F, X ), m-n-1 );
+        extFactor = power( LC( F, X ), m-n-1 );
 
     CanonicalForm result;