Kernel crashes in ReplaceAll - with or without Maximize failure
- To: mathgroup at smc.vnet.net
- Subject: [mg105181] Kernel crashes in ReplaceAll - with or without Maximize failure
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Mon, 23 Nov 2009 06:54:09 -0500 (EST)
- Reply-to: drmajorbob at yahoo.com
Two years ago this worked properly, with the output shown:
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
Maximize[{proxy, x \[Element] Integers, x <= 20}, x]
eq /. Last@%
1.96128*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/509872338168900 + (10 x)/3 - (3 x^2)/10 + x^3/150
{5567805932804389/509872338168900, {x -> 7}}
10.92
Today the same code outputs a Maximize failure and crashes the kernel:
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
Maximize[{proxy, x \[Element] Integers, x <= 20}, x]
eq /. Last@%
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150
Maximize[{1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150, x \[Element] Integers, x <= 20}, x]
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3 /. x
Ditto with this code (moving Integers to the third argument):
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
Maximize[{proxy, x <= 20}, x, Integers]
eq /. Last@%
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150
Maximize[{1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150, x <= 20}, x, Integers]
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3 /. Integers
Odder yet, the kernel doesn't crash in Fit, Rationalize, or even Maximize,
but rather, in ReplaceAll (which does nothing), yet AFTER the FE outputs a
result:
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150
Maximize[{proxy, x <= 20}, x, Integers]
Maximize[{1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150, x <= 20}, x, Integers]
eq /. Last@%
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3 /. Integers
Same here, without LessEqual:
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
Maximize[proxy, x, Integers]
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150
Maximize[1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150, x, Integers]
eq /. Last@%
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3 /. Integers
And same here, after outputting a correct result:
data = {{0, 0}, {10, 10}, {20, 0}, {30, 10}};
eq = Fit[data, {1, x, x^2, x^3}, x]
proxy = Rationalize[eq, 10^-15]
Maximize[proxy, x]
2.63678*10^-15 + 3.33333 x - 0.3 x^2 + 0.00666667 x^3
1/379250494936462 + (105718301111983 x)/31715490333595 - (
3 x^2)/10 + x^3/150
{\[Infinity], {x -> \[Infinity]}}
{$Version, $ReleaseNumber}
{"7.0 for Mac OS X x86 (64-bit) (February 19, 2009)", 1}
What's going on????
Bobby
--
DrMajorBob at yahoo.com