So, yes=MatLab calculate the values
Does this mean "Yes, we know how to make MatLab compute the values" or does it mean "Yes, we need help with making MatLab compute the values"?
The connection between MatLab and the Arduino is by way of the serial port. So, call Serial.begin() in setup, with a value to match MatLab. Then, use Serial.available() and Serial.read() to determine haow much data is available to read, and read the data one byte at a time.
Depending on how MatLab is sending the 3 values, you may have to read 3 bytes, 6 bytes, or an unknown number of bytes.