Am Mon, 15 Apr 2013 11:51:43 -0400
schrieb Steven Schveighoffer schvei...@yahoo.com:
On Mon, 15 Apr 2013 11:51:07 -0400, Steven Schveighoffer
schvei...@yahoo.com wrote:
I would suspect that the issue is floating point error. On certain
hardware, the CPU uses higher-precision 80-bit
On 04/28/2013 12:39 PM, Marco Leise wrote:
What worries me is that this jeopardizes the efforts put into
C to make floating point calculations the same under all
circumstances.
That is news to me. I remember knowing this problem from C. Perhaps
something new in the C standard that I haven't
On Sat, 13 Apr 2013 18:36:21 +0200, Jeremy DeHaan
dehaan.jerem...@gmail.com wrote:
I'm on Windows, and I my compilation was nothing more than dmd -O
-release main.d to get the issue I described.
Turns out, the problem starts here:
static const(float) pi = 3.141592654f;
If we compare
Thanks for the analysis.
On 04/20/2013 05:30 AM, Simen Kjaeraas wrote:
static const(float) pi = 3.141592654f;
If we compare that to std.math.PI, we see that they're different:
writeln( 3.141592654f - std.math.PI );
4.10207e-10
std.math.PI is a 'real'. According to the
The D book has a diagram that shows implicit conversions. All
implicit conversions from integral types to floating point go to
real, not double or float.
On 04/20/2013 11:04 AM, Casper Færgemand shortt...@gmail.com wrote:
The D book has a diagram that shows implicit conversions.
It is Figure 2.3 on page 44 of my copy of TDPL.
All implicit
conversions from integral types to floating point go to real, not double
or float.
Yes. The figure
On Mon, 15 Apr 2013 11:51:07 -0400, Steven Schveighoffer
schvei...@yahoo.com wrote:
I would suspect that the issue is floating point error. On certain
hardware, the CPU uses higher-precision 80-bit floating points. When
you store those back to doubles, the extra precision is truncated.
On Sat, 13 Apr 2013 02:07:39 -0400, Jeremy DeHaan
dehaan.jerem...@gmail.com wrote:
I have a function that will calculate a random point on a circle based
on a specified radius and total number of points. The only point in
question is the first point. I get different values when the code
I have a function that will calculate a random point on a circle
based on a specified radius and total number of points. The only
point in question is the first point. I get different values when
the code compiles in Release and Debug mode.
Here is some code:
Vector2f getPoint(uint index)
{
I'm not sure, but I suspect this is because of 80-bit intermediary float
point operation result. Its precision too excessive and gives us this
inexpectible result. But when you use an intermediary variable this
exessive intermediary result is rounded properly and you get what you
expect. See
On Sat, 13 Apr 2013 08:07:39 +0200, Jeremy DeHaan
dehaan.jerem...@gmail.com wrote:
In debug mode this works as expected. Let's say the radius is 50.
getPoint(0) returns a vector that prints X: 50 Y: 0. For some reason,
the same function will return a vector that prints X: 50 Y:
On Saturday, 13 April 2013 at 11:59:12 UTC, Simen Kjaeraas wrote:
On Sat, 13 Apr 2013 08:07:39 +0200, Jeremy DeHaan
dehaan.jerem...@gmail.com wrote:
In debug mode this works as expected. Let's say the radius is
50. getPoint(0) returns a vector that prints X: 50 Y: 0. For
some reason, the
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