bug-gnu-emacs
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

bug#25652: 26.0.50; calc says that cos(1 degree) is 0.54


From: Tino Calancha
Subject: bug#25652: 26.0.50; calc says that cos(1 degree) is 0.54
Date: Mon, 13 Feb 2017 12:40:05 +0900 (JST)
User-agent: Alpine 2.20 (DEB 67 2015-01-07)


[Forwading to the bug thread: Sorry if you receive this message twice]

address@hidden writes:

tags 25652 confirmed
retitle 25652 26.0.50; [calc] In Units Simplication + Degree mode cos(1 deg) != 
cos(1)
quit

Torsten Bronger <address@hidden> writes:
You can toggle this in calc mode with "m U".  So "m d m U 1 C m U
1 C" should exhibit the problem.  Note that you have "Deg" active
the whole time.  [...]

After havin updated to current git master, I can now reproduce this
on both of my machine.  Can you confirm?

Yes, this happens in units simplication mode.  Note that 'cos(1 deg) RET
does give 0.999.  It seems to be because of the fix for #23889 [1:
713e922243].  Tino, any ideas?

1: 2016-07-12 00:38:14 +0900 713e922243fb60d850f7b0ff83f3e2a3682f1832
  Ignore angle mode while simplifying units
Yes, my commit produced this bug.  We must revert it.  Sorry for that.
That commit was to fix Bug#23889.  It would be nice if we can fix Bug#23889 in
a new way.
In that bug the problem was that, if the user inputs a symbolic expression 
containning
an angle unit, then this unit is overriden by calc-angle-mode while simplifying 
such
expression.
That should not happen as mentioned in the manual:
(info "(calc) Trigonometric and Hyperbolic Functions")

That is,
M-x calc RET
m d ; Set calc-angle-mode to degrees.
' sin (45 deg) RET
u s ; Must insert the value of:  (sin (* 45 pi (/ 180.0)))
;; But instead, inserts the value of: (sin (* 45 (expt (/ pi 180.0) 2)))
;; i.e., it's applying (/ pi 180) twice.

I have updated the patch:
1) Revert 713e922243

2) Bind calc-angle-mode to 'rad while simplifying an expression whenever such
expression contains an unit angle.  This way, hopefully, the second factor (/ 
pi 180)
won't be applied.

Opinions, comments...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
From 1a2592409c0fcfca7826b71248d3d3d234355c13 Mon Sep 17 00:00:00 2001
From: Tino Calancha <address@hidden>
Date: Sun, 12 Feb 2017 21:14:34 +0900
Subject: [PATCH 1/2] Revert 'Ignore angle mode while simplifying units'

This commit (713e922243) cause regressions (Bug#25652).
---
 lisp/calc/calc-forms.el | 12 +++---------
 lisp/calc/calc-math.el  | 12 ++++--------
 2 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/lisp/calc/calc-forms.el b/lisp/calc/calc-forms.el
index 6aa421ec20..abf76cf07e 100644
--- a/lisp/calc/calc-forms.el
+++ b/lisp/calc/calc-forms.el
@@ -317,9 +317,7 @@ math-to-hms
         (list 'calcFunc-hms a))
        ((math-negp a)
         (math-neg (math-to-hms (math-neg a) ang)))
-       ((eq (or ang
-                 (and (not math-simplifying-units) calc-angle-mode))
-                 'rad)
+       ((eq (or ang calc-angle-mode) 'rad)
         (math-to-hms (math-div a (math-pi-over-180)) 'deg))
        ((memq (car-safe a) '(cplx polar)) a)
        (t
@@ -356,16 +354,12 @@ math-from-hms
           (if (eq (car-safe a) 'sdev)
               (math-make-sdev (math-from-hms (nth 1 a) ang)
                               (math-from-hms (nth 2 a) ang))
-            (if (eq (or ang
-                         (and (not math-simplifying-units) calc-angle-mode))
-                     'rad)
+            (if (eq (or ang calc-angle-mode) 'rad)
                 (list 'calcFunc-rad a)
               (list 'calcFunc-deg a)))))
        ((math-negp a)
         (math-neg (math-from-hms (math-neg a) ang)))
-       ((eq (or ang
-                 (and (not math-simplifying-units) calc-angle-mode))
-             'rad)
+       ((eq (or ang calc-angle-mode) 'rad)
         (math-mul (math-from-hms a 'deg) (math-pi-over-180)))
        (t
         (math-add (math-div (math-add (math-div (nth 3 a)
diff --git a/lisp/calc/calc-math.el b/lisp/calc/calc-math.el
index 2590761d53..faa318d45d 100644
--- a/lisp/calc/calc-math.el
+++ b/lisp/calc/calc-math.el
@@ -763,14 +763,12 @@ calcFunc-nroot
 (defun math-to-radians (a)   ; [N N]
   (cond ((eq (car-safe a) 'hms)
         (math-from-hms a 'rad))
-       ((and (not math-simplifying-units)
-              (memq calc-angle-mode '(deg hms)))
+       ((memq calc-angle-mode '(deg hms))
         (math-mul a (math-pi-over-180)))
        (t a)))

 (defun math-from-radians (a)   ; [N N]
-  (cond ((and (not math-simplifying-units)
-              (eq calc-angle-mode 'deg))
+  (cond ((eq calc-angle-mode 'deg)
         (if (math-constp a)
             (math-div a (math-pi-over-180))
           (list 'calcFunc-deg a)))
@@ -781,16 +779,14 @@ math-from-radians
 (defun math-to-radians-2 (a &optional force-symbolic)   ; [N N]
   (cond ((eq (car-safe a) 'hms)
         (math-from-hms a 'rad))
-       ((and (not math-simplifying-units)
-              (memq calc-angle-mode '(deg hms)))
+       ((memq calc-angle-mode '(deg hms))
         (if (or calc-symbolic-mode force-symbolic)
             (math-div (math-mul a '(var pi var-pi)) 180)
           (math-mul a (math-pi-over-180))))
        (t a)))

 (defun math-from-radians-2 (a &optional force-symbolic)   ; [N N]
-  (cond ((and (not math-simplifying-units)
-              (memq calc-angle-mode '(deg hms)))
+  (cond ((memq calc-angle-mode '(deg hms))
         (if (or calc-symbolic-mode force-symbolic)
             (math-div (math-mul 180 a) '(var pi var-pi))
           (math-div a (math-pi-over-180))))
--
2.11.0

From b1b6f62f5baa8023a7b5d45b1d30399c8e8f82a2 Mon Sep 17 00:00:00 2001
From: Tino Calancha <address@hidden>
Date: Sun, 12 Feb 2017 21:45:47 +0900
Subject: [PATCH 2/2] Prevent from override input angle unit while simplifying

Ignore calc-angle-mode while simplifying if the expression
contains angle units (Bug#23899).
* lisp/calc/calc-alg.el (calc-input-angle-units): New defun.
(math-simplify): If TOP-EXPR contains angle units, then bind
calc-angle-mode to 'rad.
* test/lisp/calc/calc-tests.el (test-calc-23889): New test.
---
 lisp/calc/calc-alg.el        |  9 +++++++++
 test/lisp/calc/calc-tests.el | 46 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/lisp/calc/calc-alg.el b/lisp/calc/calc-alg.el
index 4e63d238c7..9db901a975 100644
--- a/lisp/calc/calc-alg.el
+++ b/lisp/calc/calc-alg.el
@@ -355,10 +355,19 @@ math-hyperbolic-trig-rewrite
 ;; math-simplify-step, which is called by math-simplify.
 (defvar math-top-only)

+(defun calc-input-angle-units (input)
+  (cond ((math-expr-contains input '(var deg var-deg)) 'deg)
+        ((math-expr-contains input '(var rad var-rad)) 'rad)
+        ((math-expr-contains input '(var hms var-hms)) 'hms)
+        (t nil)))
+
 ;; math-normalize-error is declared in calc.el.
 (defvar math-normalize-error)
 (defun math-simplify (top-expr)
   (let ((math-simplifying t)
+        (calc-angle-mode (if (calc-input-angle-units top-expr)
+                             'rad
+                           calc-angle-mode))
        (math-top-only (consp calc-simplify-mode))
        (simp-rules (append (and (calc-has-rules 'var-AlgSimpRules)
                                 '((var AlgSimpRules var-AlgSimpRules)))
diff --git a/test/lisp/calc/calc-tests.el b/test/lisp/calc/calc-tests.el
index 8f56d48d01..45b735c3c6 100644
--- a/test/lisp/calc/calc-tests.el
+++ b/test/lisp/calc/calc-tests.el
@@ -86,6 +86,52 @@ calc-tests-simple
                                               (math-read-expr "1m") "cm")
                            '(* -100 (var cm var-cm)))))

+(ert-deftest test-calc-23889 ()
+  "Test for http://debbugs.gnu.org/23889 and 25652."
+  (dolist (mode '(deg rad))
+    (let ((calc-angle-mode mode))
+      ;; If user inputs angle units, then should ignore `calc-angle-mode'.
+      (should (string= "5253"
+                       (substring
+                        (number-to-string
+                         (nth 1
+                              (math-simplify-units
+                               '(calcFunc-cos (* 45 (var rad var-rad))))))
+                        0 4)))
+      (should (string= "7071"
+                       (substring
+                        (number-to-string
+                         (nth 1
+                              (math-simplify-units
+                               '(calcFunc-cos (* 45 (var deg var-deg))))))
+                        0 4)))
+      (should (string= "8939"
+                       (substring
+                        (number-to-string
+                         (nth 1
+                              (math-simplify-units
+                               '(+ (calcFunc-sin (* 90 (var rad var-rad)))
+                                   (calcFunc-cos (* 90 (var deg var-deg)))))))
+                        0 4)))
+      (should (string= "5519"
+                       (substring
+                        (number-to-string
+                         (nth 1
+                              (math-simplify-units
+                               '(+ (calcFunc-sin (* 90 (var deg var-deg)))
+                                   (calcFunc-cos (* 90 (var rad var-rad)))))))
+                        0 4)))
+      ;; If user doesn't input units, then must use `calc-angle-mode'.
+      (should (string= (if (eq calc-angle-mode 'deg)
+                           "9998"
+                         "5403")
+                       (substring
+                        (number-to-string
+                         (nth 1
+                              (math-simplify-units
+                               '(calcFunc-cos 1))))
+                        0 4))))))
+
 (provide 'calc-tests)
 ;;; calc-tests.el ends here

--
2.11.0

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
In GNU Emacs 26.0.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.7)
 of 2017-02-12
Repository revision: 862d6438cfa6c6c035033697751f3d002357b024





reply via email to

[Prev in Thread] Current Thread [Next in Thread]