git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@5258 f3b2605a-c512-4ea7-a41b-209d697bcdaa

src/variable.cpp

@@ -608,7 +608,7 @@ void Variable::copy(int narg, char **from, char **to)
      constant = PI
      thermo keyword = ke, vol, atoms, ...
      math operation = (),-x,x+y,x-y,x*y,x/y,x^y,
-                      x==y,x!=y,x<y,x<=y,x>y,x>=y,
+                      x==y,x!=y,x<y,x<=y,x>y,x>=y,x&&y,x||y,
                       sqrt(x),exp(x),ln(x),log(x),
 		      sin(x),cos(x),tan(x),asin(x),atan2(y,x),...
      group function = count(group), mass(group), xcm(group,x), ...
@@ -3069,3 +3069,175 @@ void Variable::print_tree(Tree *tree, int level)
   if (tree->right) print_tree(tree->right,level+1);
   return;
 }
+
+/* ----------------------------------------------------------------------
+   recursive evaluation of string str
+   called from "if" command in input script
+   str is a boolean expression containing one or more items:
+     number = 0.0, -5.45, 2.8e-4, ...
+     math operation = (),x==y,x!=y,x<y,x<=y,x>y,x>=y,x&&y,x||y
+------------------------------------------------------------------------- */
+
+double Variable::evaluate_boolean(char *str)
+{
+  int op,opprevious;
+  double value1,value2;
+  char onechar;
+  char *ptr;
+
+  double argstack[MAXLEVEL];
+  int opstack[MAXLEVEL];
+  int nargstack = 0;
+  int nopstack = 0;
+
+  int i = 0;
+  int expect = ARG;
+
+  while (1) {
+    onechar = str[i];
+    
+    // whitespace: just skip
+    
+    if (isspace(onechar)) i++;
+    
+    // ----------------
+    // parentheses: recursively evaluate contents of parens
+    // ----------------
+    
+    else if (onechar == '(') {
+      if (expect == OP) error->all("Invalid Boolean syntax in if command");
+      expect = OP;
+      
+      char *contents;
+      i = find_matching_paren(str,i,contents);
+      i++;
+      
+      // evaluate contents and push on stack
+      
+      argstack[nargstack++] = evaluate_boolean(contents);
+      
+      delete [] contents;
+      
+    // ----------------
+    // number: push value onto stack
+    // ----------------
+      
+    } else if (isdigit(onechar) || onechar == '.') {
+      if (expect == OP) error->all("Invalid Boolean syntax in if command");
+      expect = OP;
+      
+      // istop = end of number, including scientific notation
+      
+      int istart = i;
+      while (isdigit(str[i]) || str[i] == '.') i++;
+      if (str[i] == 'e' || str[i] == 'E') {
+	i++;
+	if (str[i] == '+' || str[i] == '-') i++;
+	while (isdigit(str[i])) i++;
+      }
+      int istop = i - 1;
+      
+      int n = istop - istart + 1;
+      char *number = new char[n+1];
+      strncpy(number,&str[istart],n);
+      number[n] = '\0';
+      
+      argstack[nargstack++] = atof(number);
+      
+      delete [] number;
+      
+    // ----------------
+    // Boolean operator, including end-of-string
+    // ----------------
+      
+    } else if (strchr("<>=!&|\0",onechar)) {
+      if (onechar == '=') {
+	if (str[i+1] != '=') 
+	  error->all("Invalid Boolean syntax in if command");
+	op = EQ;
+	i++;
+      } else if (onechar == '!') {
+	if (str[i+1] != '=') 
+	  error->all("Invalid Boolean syntax in if command");
+	op = NE;
+	i++;
+      } else if (onechar == '<') {
+	if (str[i+1] != '=') op = LT;
+	else {
+	  op = LE;
+	  i++;
+	}
+      } else if (onechar == '>') {
+	if (str[i+1] != '=') op = GT;
+	else {
+	  op = GE;
+	  i++;
+	}
+      } else if (onechar == '&') {
+	if (str[i+1] != '&') 
+	  error->all("Invalid Boolean syntax in if command");
+	op = AND;
+	i++;
+      } else if (onechar == '|') {
+	if (str[i+1] != '|') 
+	  error->all("Invalid Boolean syntax in if command");
+	op = OR;
+	i++;
+      } else op = DONE;
+      
+      i++;
+      
+      if (expect == ARG) error->all("Invalid Boolean syntax in if command");
+      expect = ARG;
+      
+      // evaluate stack as deep as possible while respecting precedence
+      // before pushing current op onto stack
+      
+      while (nopstack && precedence[opstack[nopstack-1]] >= precedence[op]) {
+	opprevious = opstack[--nopstack];
+	
+	value2 = argstack[--nargstack];
+	value1 = argstack[--nargstack];
+	
+	if (opprevious == EQ) {
+	  if (value1 == value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == NE) {
+	  if (value1 != value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == LT) {
+	  if (value1 < value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == LE) {
+	  if (value1 <= value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == GT) {
+	  if (value1 > value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == GE) {
+	  if (value1 >= value2) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == AND) {
+	  if (value1 != 0.0 && value2 != 0.0) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	} else if (opprevious == OR) {
+	  if (value1 != 0.0 || value2 != 0.0) argstack[nargstack++] = 1.0;
+	  else argstack[nargstack++] = 0.0;
+	}
+      }
+      
+      // if end-of-string, break out of entire formula evaluation loop
+      
+      if (op == DONE) break;
+      
+      // push current operation onto stack
+      
+      opstack[nopstack++] = op;
+      
+    } else error->all("Invalid Boolean syntax in if command");
+  }
+
+  if (nopstack) error->all("Invalid Boolean syntax in if command");
+  if (nargstack != 1) error->all("Invalid Boolean syntax in if command");
+  return argstack[0];
+}