Math feature does not correct support channel names such as voltage0_i and voltage0_q

[Brent K]

For certain IIO devices (such as the ADRV9002 in MIMO mode), the channel names of the devices are suffixed with _i and _q, while retaining the same channel number.

The eval function in math_expression_generator.h assumes the channel number is unique, and incorrectly selects the index into the channels_data array. For example, the math expression atanf(voltage0_q / voltage0_i) will evaluate to atanf(channels_data[0] / channels_data[0]). Channel selection should likely be based on name rather than assuming unique channel numbers.

for (pos = match; *pos; pos++) {
	if (g_ascii_isdigit(*pos))
		break;
}
if ((size_t)(pos - match) < strlen(match))
	index = atoi(pos);
else
	index = 0;

[cristina-suteu]

Hi,
We are looking into this