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Fixes a numerical accuracy issue in the pitch search

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The energy "sliding window" was using double accumulation with
float multiplications. This forces the multiplications to be
double as well.
This commit is contained in:
Jean-Marc Valin 2011-10-12 12:58:52 -04:00
parent d84c8d1fd8
commit d5158a42d1
2 changed files with 8 additions and 8 deletions
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12
silk/float/energy_FLP.c
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@ -41,18 +41,18 @@ double silk_energy_FLP(
double result;
/* 4x unrolled loop */
result = 0.0f;
result = 0.0;
dataSize4 = dataSize & 0xFFFC;
for( i = 0; i < dataSize4; i += 4 ) {
result += data[ i + 0 ] * data[ i + 0 ] +
data[ i + 1 ] * data[ i + 1 ] +
data[ i + 2 ] * data[ i + 2 ] +
data[ i + 3 ] * data[ i + 3 ];
result += data[ i + 0 ] * (double)data[ i + 0 ] +
data[ i + 1 ] * (double)data[ i + 1 ] +
data[ i + 2 ] * (double)data[ i + 2 ] +
data[ i + 3 ] * (double)data[ i + 3 ];
}
/* add any remaining products */
for( ; i < dataSize; i++ ) {
result += data[ i ] * data[ i ];
result += data[ i ] * (double)data[ i ];
}
silk_assert( result >= 0.0 );

4
silk/float/pitch_analysis_core_FLP.c
View file

@ -610,11 +610,11 @@ calculated recursively.
lag_diff = ( matrix_ptr( Lag_range_ptr, k, 1, 2 ) - matrix_ptr( Lag_range_ptr, k, 0, 2 ) + 1 );
for( i = 1; i < lag_diff; i++ ) {
/* remove part outside new window */
energy -= basis_ptr[sf_length - i] * basis_ptr[sf_length - i];
energy -= basis_ptr[sf_length - i] * (double)basis_ptr[sf_length - i];
silk_assert( energy >= 0.0 );
/* add part that comes into window */
energy += basis_ptr[ -i ] * basis_ptr[ -i ];
energy += basis_ptr[ -i ] * (double)basis_ptr[ -i ];
silk_assert( energy >= 0.0 );
silk_assert( lag_counter < SCRATCH_SIZE );
scratch_mem[lag_counter] = (silk_float)energy;