From 0c7be2c208f3f173b3d8913e55aeb3b731fcf3f7 Mon Sep 17 00:00:00 2001
From: Travis Oliphant <oliphant@enthought.com>
Date: Mon, 31 Jul 2006 20:33:49 +0000
Subject: Fix longdouble machar problem (iterations too low)

---
 numpy/lib/machar.py | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

(limited to 'numpy/lib/machar.py')

diff --git a/numpy/lib/machar.py b/numpy/lib/machar.py
index e66583774..9d0e08e45 100644
--- a/numpy/lib/machar.py
+++ b/numpy/lib/machar.py
@@ -58,7 +58,8 @@ class MachAr(object):
           float_to_str - convert array float to str
           title        - description of used floating point numbers
         """
-        max_iter = range(1000)
+        max_iterN = 10000
+        msg = "Did not converge after %d tries with %s"
         one = float_conv(1)
         two = one + one
         zero = one - one
@@ -66,30 +67,30 @@ class MachAr(object):
         # Do we really need to do this?  Aren't they 2 and 2.0?
         # Determine ibeta and beta
         a = one
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             a = a + a
             temp = a + one
             temp1 = temp - a
             if any(temp1 - one != zero):
                 break
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         b = one
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             b = b + b
             temp = a + b
             itemp = int_conv(temp-a)
             if any(itemp != 0):
                 break
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         ibeta = itemp
         beta = float_conv(ibeta)
 
         # Determine it and irnd
         it = -1
         b = one
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             it = it + 1
             b = b * beta
             temp = b + one
@@ -97,18 +98,18 @@ class MachAr(object):
             if any(temp1 - one != zero):
                 break
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
 
         betah = beta / two
         a = one
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             a = a + a
             temp = a + one
             temp1 = temp - a
             if any(temp1 - one != zero):
                 break
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         temp = a + betah
         irnd = 0
         if any(temp-a != zero):
@@ -125,7 +126,7 @@ class MachAr(object):
         for i in range(negep):
             a = a * betain
         b = a
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             temp = one - a
             if any(temp-one != zero):
                 break
@@ -136,7 +137,7 @@ class MachAr(object):
                 raise RuntimeError, "could not determine machine tolerance " \
                                     "for 'negep', locals() -> %s" % (locals())
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         negep = -negep
         epsneg = a
 
@@ -144,14 +145,14 @@ class MachAr(object):
         machep = - it - 3
         a = b
 
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             temp = one + a
             if any(temp-one != zero):
                 break
             a = a * beta
             machep = machep + 1
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         eps = a
 
         # Determine ngrd
@@ -166,7 +167,7 @@ class MachAr(object):
         z = betain
         t = one + eps
         nxres = 0
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             y = z
             z = y*y
             a = z*one # Check here for underflow
@@ -179,7 +180,7 @@ class MachAr(object):
             i = i + 1
             k = k + k
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         if ibeta != 10:
             iexp = i + 1
             mx = k + k
@@ -192,7 +193,7 @@ class MachAr(object):
             mx = iz + iz - 1
 
         # Determine minexp and xmin
-        for _ in max_iter:
+        for _ in xrange(max_iterN):
             xmin = y
             y = y * betain
             a = y * one
@@ -207,7 +208,7 @@ class MachAr(object):
             else:
                 break
         else:
-            raise RuntimeError
+            raise RuntimeError, msg % (_, one.dtype)
         minexp = -k
 
         # Determine maxexp, xmax
-- 
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