public void setCaldera(float caldera) throws Exception {
        if (caldera < 0.0f || caldera > 1.0f) {
            throw new Exception(
                    "Caldera level must be " + "between 0 and 1");
        }
        this.caldera = caldera;
    }
<code>setCaldera</code> sets the level at which a peak will be
inverted.

@param caldera the level at which a peak will be inverted. This must be
             between 0 and 1, as it is represented as a percentage.
@throws Exception if caldera is not between 0 and 1.
jme3-terrain/src/main/java/com/jme3/terrain/heightmap/ParticleDepositionHeightMap.java