diff options
Diffstat (limited to 'lisp/calc/calcalg2.el')
| -rw-r--r-- | lisp/calc/calcalg2.el | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/lisp/calc/calcalg2.el b/lisp/calc/calcalg2.el index 2a463009e58..7e8484ea79f 100644 --- a/lisp/calc/calcalg2.el +++ b/lisp/calc/calcalg2.el @@ -738,8 +738,12 @@ (setcar (cdr cur-record) 'cancelled))) (math-replace-integral-parts (car expr))))))) +(defvar math-linear-subst-tried t + "Non-nil means that a linear substitution has been tried.") + (defun math-do-integral (expr) - (let (t1 t2) + (let ((math-linear-subst-tried nil) + t1 t2) (or (cond ((not (math-expr-contains expr math-integ-var)) (math-mul expr math-integ-var)) ((equal expr math-integ-var) @@ -977,7 +981,7 @@ ;; Integration by substitution, for various likely sub-expressions. ;; (In first pass, we look only for sub-exprs that are linear in X.) - (or (if math-enable-subst + (or (if math-linear-subst-tried (math-integ-try-substitutions expr) (math-integ-try-linear-substitutions expr)) @@ -1189,6 +1193,7 @@ ;;; Look for substitutions of the form u = a x + b. (defun math-integ-try-linear-substitutions (sub-expr) + (setq math-linear-subst-tried t) (and (not (Math-primp sub-expr)) (or (and (not (memq (car sub-expr) '(+ - * / neg))) (not (and (eq (car sub-expr) '^) |