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/* { dg-do compile } */
/* { dg-options "-O1 -fscalar-evolutions -fdump-tree-scev-details" } */
/* That's a reduced testcase of one of my favourite simulation programs.
This is also known under the name: "Newton's falling apple".
The general version is known under the name: "the N-body simulation problem".
The physics terminology is the best to describe the scalar evolution algorithm:
- first determine the initial conditions of the system,
- then analyze its evolution.
*/
double Newton_s_apple ()
{
/* Initial conditions. */
double g = -10.0;
double speed_z = 0;
double altitude = 3000;
double delta_t = 0.1;
double total_time = 0;
/* Laws of evolution. */
while (altitude > 0.0)
{
speed_z += g * delta_t;
altitude += speed_z * delta_t;
total_time += delta_t;
}
return total_time;
}
/*
speed_z -> {0.0, +, -1.0e+0}_1
altitude -> {3.0e+3, +, {(0.0 + -1.0e+0) * 1.00000000000000005551115123125782702118158340454e-1, +, -1.0e+0 * 1.00000000000000005551115123125782702118158340454e-1}_1}_1
*/
/* FIXME. */
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