Changeset 163

Timestamp:

12/17/07 03:32:00 (10 months ago)

Author:

Don Clugston

Message:

Folding of unary minus -- it gets eliminated in the majority of cases.

Files:

• trunk/blade/Blade.d (modified) (1 diff)
• trunk/blade/BladeSimplify.d (modified) (9 diffs)

trunk/blade/Blade.d

@@ -149 +149 @@
-            }
-            // TODO: disallow asm if any non-int/not FP types are used.
- // BUG: assume asm can always do scalars
+
-        }
-        if (r>'1') return VecExpressionType.DExpression; // can only do scalars and vectors right now.

trunk/blade/BladeSimplify.d

@@ -14 +14 @@
-*      be moved to every vector inside A.
-*    - Use associativity of *: A*(B*C[]) == (A*B)*C[]
-*    - Use * distributive law over + and -. (Not strictly correct).
-* (D) Expression standardisation 
-*    - Move multiplies to left: Convert A[]*B into B*A[] (assumes * is commutative,
@@ -421 +420 @@
-{
-    char [] expr;       // vector or matrix expression; empty for a pure scalar expression
-
+. or "-" for unary minus
-}
-
@@ -438 +437 @@
-            ScalarFold left = doVisit(this_,args[0]);
-            ScalarFold right = doVisit(this_, args[1]);
-            char [] s = left.multiplier;
-            if (s.length>0 && right.multiplier.length>0) s~= "*"  ~ right.multiplier;
-            if (s.length>0) s ~="*";
-            return ScalarFold("", combineMul(combineMul(left.multiplier, right.multiplier), func ~ "(" ~ left.expr ~ "," ~ right.expr ~ ")"));
-        } else {
@@ -451 +447 @@
-            // Fold unary minus into a multiply, if possible.
-            ScalarFold left = doVisit(this_, expr);
-
-
+
+
+
-        } else if (op=="+") { // just ignore unary plus
-            return doVisit(this_, expr);        
@@ -485 +482 @@
-        if (op=="*=") {
-            assert(first.multiplier=="" && second.expr=="", "BLADE ICE");
+            assert(second.multiplier!="-", "BLADE ICE"); // this would be a*=-b, where b is a vector
-            if (second.multiplier.length>1)  return ScalarFold(wrapInParens(first.expr) ~ op ~ " {" ~ wrapInParens(second.multiplier) ~ "} ",""); 
-            else return ScalarFold(wrapInParens(first.expr) ~ op ~ wrapInParens(second.multiplier),""); 
@@ -492 +490 @@
-        }
-        if (first.expr=="" && second.expr=="") { // both are 100% scalars -- it remains a scalar.
+            // Note: neither can be a unary minus.
-            return ScalarFold("",
-            wrapInParens(combineMul(first.expr, first.multiplier)) ~ op ~
-            wrapInParens(combineMul(second.expr, second.multiplier)));
-        }
+        // BUG: Should also do +=, -=.
+        if (op=="-" && second.multiplier=="-") {
+            if (first.multiplier=="-") {
+                // convert (-a)-(-b) into b-a
+                return ScalarFold(wrapInParens(second.expr) ~ "-" ~
+                wrapInParens(first.expr), "");
+            }
+            // convert a-(-b) into a+b
+            return ScalarFold(wrapInParens(combineMulWithCompound(first.expr, first.multiplier)) ~ "+" ~
+            wrapInParens(second.expr), "");
+        }
+        if (op=="+" && second.multiplier=="-") {
+            // convert a+(-b) into a-b
+            return ScalarFold(wrapInParens(combineMulWithCompound(first.expr, first.multiplier)) ~ "-" ~
+            wrapInParens(second.expr), "");
+        }
+        if (op=="+" && first.multiplier=="-") {
+            // convert (-a)+b into b-a
+            return ScalarFold(wrapInParens(combineMulWithCompound(second.expr, second.multiplier)) ~ "-" ~
+            wrapInParens(first.expr), "");
+        }
+        if (op=="-" && second.multiplier!="") {
+            // convert a-b into a+(-b) where possible.
+            return ScalarFold(wrapInParens(combineMulWithCompound(first.expr, first.multiplier)) ~ "+" ~
+            wrapInParens(combineMulWithCompound(second.expr, "-" ~ wrapInParens(second.multiplier))), "");
+        }
-        return ScalarFold(wrapInParens(combineMulWithCompound(first.expr, first.multiplier)) ~ op ~
-            wrapInParens(combineMulWithCompound(second.expr, second.multiplier)), "");
@@ -505 +530 @@
-    if (left.length==0) return right;
-    if (right.length==0) return left;
+    if (left=="-" && right=="-") return "";
+    if (left=="-") return "-" ~ wrapInParens(right);
+    if (right=="-") return "-" ~ wrapInParens(left);
-    return wrapInParens(left) ~ "*" ~ wrapInParens(right);
-}
@@ -513 +541 @@
-    assert(left.length>0);
-    if (right.length==0) return left;
+    if (right=="-") return "-" ~ wrapInParens(left);    
-    if (right.length==1) return wrapInParens(left) ~ "*" ~ right;
-    return wrapInParens(left) ~ "* {" ~ wrapInParens(right) ~ "} ";    
@@ -528 +557 @@
-    assert(foldScalars("A*=(B*C)", "100")== "A*= {(B*C)} ");
-    assert(foldScalars("d(A,(A*d(A,A)))", "1")==" {(d(A,A))*(d(A,A))} ");
-
+
+
+
+
+
+
+