#include "MusimatChapter9.h"Go to the source code of this file.
Functions | |
| MusimatChapter9Section (C091406a) | |
| RealList Reference | accumulate (RealList Reference L) |
| Static Void | para1 () |
| RealList Reference accumulate | ( | RealList Reference | L ) |
Definition at line 16 of file C091406a.cpp.
{
For(Integer i = 1; i < Length(L); i = i + 1) {
L[i] = L[i] + L[i - 1];
}
Return(L);
}
| MusimatChapter9Section | ( | C091406a | ) |
Definition at line 2 of file C091406a.cpp.
References para1().
{
Print("*** Accumulation ***");
/*****************************************************************************
Accumulation
If we index the y-axis of figure 9.22 with a random value in the unit interval, the corresponding
x-axis value will be one of the 12 pitches of the scale. Furthermore, the choice will more likely
fall on a step that occupies a wider footprint on the y-axis, corresponding in this case to the
lower pitches of the scale, just as we wanted. We can create the cumulative distribution function
in figure 9.22 as follows:
*****************************************************************************/
para1(); // Step into this function to continue.
}
| Static Void para1 | ( | ) |
Definition at line 23 of file C091406a.cpp.
{
/*****************************************************************************
Starting with the second element in the list (indexed as 1), we replace this element with its original
value plus the value of the previous element. As we proceed through the list, each list element will
be equal to itself plus all previous elements. Given the preparation of the RealList r performed
above, Print(accumulate(r)); prints {0.15, 0.29, 0.42, 0.54, 0.64, 0.73, 0.81,
0.87, 0.92, 0.96, 0.99, 1.0}.
We have prepared the cumulative distribution function, and now we can access it with a random
value to select a pitch. Pick a number in the unit interval to be the next note of the melody:
*****************************************************************************/
Real R = Random();
Print(R);
/*****************************************************************************
R will fall within the range of one of the 12 steps in figure 9.22 because both Random() and the
cumulative distribution function exactly span the unit interval, 0 to 1. For example, if R equals 0.1,
then by inspection of figure 9.22, we can see that R lies within the first step, which covers the inter-
val [0, 0.15], so the pitch that this value of R selects is C.
*****************************************************************************/
}
1.7.2