code: public void setYValues(double yOffset, double yInterval) {
      // Update the y-values according to the offset and interval.
      yValues = new Object[zValues.length];
      for (int i = 0; i < zValues.length; i++) {
        yValues[i] = yOffset + (i * yInterval);
      }
    }
docs: Sets the y-values which are plotted along the y-axis. The y-values are calculated based upon
  the indexes of the z-values array:
  
  <pre>
  
  {@code
  
  <pre>
  y-value = y-offset + (column-index * y-interval)
  
  </pre>
  
  
  }
  </pre>
  
  <p>
  The y-interval defines the gap between each y-value and the y-offset is applied to each value
  to offset them all from zero.
  
  <p>
  Alternatively the y-values can be set more directly with the <code>setYValues(Object[])</code>
  method.
  
  @param yOffset an offset value to be applied to the index of each z-value element.
  @param yInterval an interval that will separate each y-value item.