本文整理了Java中java.lang.Math.acos()方法的一些代码示例，展示了Math.acos()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Math.acos()方法的具体详情如下：
包路径：java.lang.Math
类名称：Math
方法名：acos

Math.acos介绍

[英]Returns the closest double approximation of the arc cosine of the argument within the range [0..pi]. The returned result is within 1 ulp (unit in the last place) of the real result.

Special cases:

• acos((anything > 1) = NaN
• acos((anything < -1) = NaN
• acos(NaN) = NaN
  [中]返回[0..pi]范围内参数的弧余弦的最接近的双近似值。返回的结果在实际结果的1 ulp（最后一位的单位）范围内。
  特殊情况：
  *acos（（任何>1）=NaN
  *acos（（任何小于-1的项）=NaN
  *助理文书主任（南）=南

代码示例

代码示例来源：origin: stackoverflow.com

private double meterDistanceBetweenPoints(float lat_a, float lng_a, float lat_b, float lng_b) {
  float pk = (float) (180.f/Math.PI);

  float a1 = lat_a / pk;
  float a2 = lng_a / pk;
  float b1 = lat_b / pk;
  float b2 = lng_b / pk;

  float t1 = FloatMath.cos(a1)*FloatMath.cos(a2)*FloatMath.cos(b1)*FloatMath.cos(b2);
  float t2 = FloatMath.cos(a1)*FloatMath.sin(a2)*FloatMath.cos(b1)*FloatMath.sin(b2);
  float t3 = FloatMath.sin(a1)*FloatMath.sin(b1);
  double tt = Math.acos(t1 + t2 + t3);

  return 6366000*tt;
}

代码示例来源：origin: libgdx/libgdx

/** Get the angle in radians of the rotation this quaternion represents. Does not normalize the quaternion. Use
 * {@link #getAxisAngleRad(Vector3)} to get both the axis and the angle of this rotation. Use
 * {@link #getAngleAroundRad(Vector3)} to get the angle around a specific axis.
 * @return the angle in radians of the rotation */
public float getAngleRad () {
  return (float)(2.0 * Math.acos((this.w > 1) ? (this.w / len()) : this.w));
}

代码示例来源：origin: libgdx/libgdx

/** Get the angle in radians of the rotation this quaternion represents. Does not normalize the quaternion. Use
 * {@link #getAxisAngleRad(Vector3)} to get both the axis and the angle of this rotation. Use
 * {@link #getAngleAroundRad(Vector3)} to get the angle around a specific axis.
 * @return the angle in radians of the rotation */
public float getAngleRad () {
  return (float)(2.0 * Math.acos((this.w > 1) ? (this.w / len()) : this.w));
}

代码示例来源：origin: apache/incubator-druid

@Override
 protected ExprEval eval(double param)
 {
  return ExprEval.of(Math.acos(param));
 }
}

代码示例来源：origin: libgdx/libgdx

/** Get the axis-angle representation of the rotation in radians. The supplied vector will receive the axis (x, y and z values)
 * of the rotation and the value returned is the angle in radians around that axis. Note that this method will alter the
 * supplied vector, the existing value of the vector is ignored. </p> This will normalize this quaternion if needed. The
 * received axis is a unit vector. However, if this is an identity quaternion (no rotation), then the length of the axis may be
 * zero.
 * 
 * @param axis vector which will receive the axis
 * @return the angle in radians
 * @see <a href="http://en.wikipedia.org/wiki/Axis%E2%80%93angle_representation">wikipedia</a>
 * @see <a href="http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToAngle">calculation</a> */
public float getAxisAngleRad (Vector3 axis) {
  if (this.w > 1) this.nor(); // if w>1 acos and sqrt will produce errors, this cant happen if quaternion is normalised
  float angle = (float)(2.0 * Math.acos(this.w));
  double s = Math.sqrt(1 - this.w * this.w); // assuming quaternion normalised then w is less than 1, so term always positive.
  if (s < MathUtils.FLOAT_ROUNDING_ERROR) { // test to avoid divide by zero, s is always positive due to sqrt
    // if s close to zero then direction of axis not important
    axis.x = this.x; // if it is important that axis is normalised then replace with x=1; y=z=0;
    axis.y = this.y;
    axis.z = this.z;
  } else {
    axis.x = (float)(this.x / s); // normalise axis
    axis.y = (float)(this.y / s);
    axis.z = (float)(this.z / s);
  }
  return angle;
}

代码示例来源：origin: libgdx/libgdx

/** Get the axis-angle representation of the rotation in radians. The supplied vector will receive the axis (x, y and z values)
 * of the rotation and the value returned is the angle in radians around that axis. Note that this method will alter the
 * supplied vector, the existing value of the vector is ignored. </p> This will normalize this quaternion if needed. The
 * received axis is a unit vector. However, if this is an identity quaternion (no rotation), then the length of the axis may be
 * zero.
 * 
 * @param axis vector which will receive the axis
 * @return the angle in radians
 * @see <a href="http://en.wikipedia.org/wiki/Axis%E2%80%93angle_representation">wikipedia</a>
 * @see <a href="http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToAngle">calculation</a> */
public float getAxisAngleRad (Vector3 axis) {
  if (this.w > 1) this.nor(); // if w>1 acos and sqrt will produce errors, this cant happen if quaternion is normalised
  float angle = (float)(2.0 * Math.acos(this.w));
  double s = Math.sqrt(1 - this.w * this.w); // assuming quaternion normalised then w is less than 1, so term always positive.
  if (s < MathUtils.FLOAT_ROUNDING_ERROR) { // test to avoid divide by zero, s is always positive due to sqrt
    // if s close to zero then direction of axis not important
    axis.x = this.x; // if it is important that axis is normalised then replace with x=1; y=z=0;
    axis.y = this.y;
    axis.z = this.z;
  } else {
    axis.x = (float)(this.x / s); // normalise axis
    axis.y = (float)(this.y / s);
    axis.z = (float)(this.z / s);
  }
  return angle;
}

代码示例来源：origin: libgdx/libgdx

float theta = (float)Math.acos(w / norm);

代码示例来源：origin: libgdx/libgdx

/** Get the angle in radians of the rotation around the specified axis. The axis must be normalized.
 * @param axisX the x component of the normalized axis for which to get the angle
 * @param axisY the y component of the normalized axis for which to get the angle
 * @param axisZ the z component of the normalized axis for which to get the angle
 * @return the angle in radians of the rotation around the specified axis */
public float getAngleAroundRad (final float axisX, final float axisY, final float axisZ) {
  final float d = Vector3.dot(this.x, this.y, this.z, axisX, axisY, axisZ);
  final float l2 = Quaternion.len2(axisX * d, axisY * d, axisZ * d, this.w);
  return MathUtils.isZero(l2) ? 0f : (float)(2.0 * Math.acos(MathUtils.clamp(
    (float)((d < 0 ? -this.w : this.w) / Math.sqrt(l2)), -1f, 1f)));
}

代码示例来源：origin: libgdx/libgdx

@Override
public Vector3 setToRandomDirection () {
  float u = MathUtils.random();
  float v = MathUtils.random();
  float theta = MathUtils.PI2 * u; // azimuthal angle
  float phi = (float)Math.acos(2f * v - 1f); // polar angle
  return this.setFromSpherical(theta, phi);
}

代码示例来源：origin: libgdx/libgdx

/** Set this quaternion to the rotation between two vectors.
 * @param v1 The base vector, which should be normalized.
 * @param v2 The target vector, which should be normalized.
 * @return This quaternion for chaining */
public Quaternion setFromCross (final Vector3 v1, final Vector3 v2) {
  final float dot = MathUtils.clamp(v1.dot(v2), -1f, 1f);
  final float angle = (float)Math.acos(dot);
  return setFromAxisRad(v1.y * v2.z - v1.z * v2.y, v1.z * v2.x - v1.x * v2.z, v1.x * v2.y - v1.y * v2.x, angle);
}

代码示例来源：origin: libgdx/libgdx

/** Get the angle in radians of the rotation around the specified axis. The axis must be normalized.
 * @param axisX the x component of the normalized axis for which to get the angle
 * @param axisY the y component of the normalized axis for which to get the angle
 * @param axisZ the z component of the normalized axis for which to get the angle
 * @return the angle in radians of the rotation around the specified axis */
public float getAngleAroundRad (final float axisX, final float axisY, final float axisZ) {
  final float d = Vector3.dot(this.x, this.y, this.z, axisX, axisY, axisZ);
  final float l2 = Quaternion.len2(axisX * d, axisY * d, axisZ * d, this.w);
  return MathUtils.isZero(l2) ? 0f : (float)(2.0 * Math.acos(MathUtils.clamp(
    (float)((d < 0 ? -this.w : this.w) / Math.sqrt(l2)), -1f, 1f)));
}

代码示例来源：origin: libgdx/libgdx

@Override
public Vector3 setToRandomDirection () {
  float u = MathUtils.random();
  float v = MathUtils.random();
  float theta = MathUtils.PI2 * u; // azimuthal angle
  float phi = (float)Math.acos(2f * v - 1f); // polar angle
  return this.setFromSpherical(theta, phi);
}

代码示例来源：origin: libgdx/libgdx

/** Set this quaternion to the rotation between two vectors.
 * @param v1 The base vector, which should be normalized.
 * @param v2 The target vector, which should be normalized.
 * @return This quaternion for chaining */
public Quaternion setFromCross (final Vector3 v1, final Vector3 v2) {
  final float dot = MathUtils.clamp(v1.dot(v2), -1f, 1f);
  final float angle = (float)Math.acos(dot);
  return setFromAxisRad(v1.y * v2.z - v1.z * v2.y, v1.z * v2.x - v1.x * v2.z, v1.x * v2.y - v1.y * v2.x, angle);
}

代码示例来源：origin: libgdx/libgdx

/** Set this quaternion to the rotation between two vectors.
 * @param x1 The base vectors x value, which should be normalized.
 * @param y1 The base vectors y value, which should be normalized.
 * @param z1 The base vectors z value, which should be normalized.
 * @param x2 The target vector x value, which should be normalized.
 * @param y2 The target vector y value, which should be normalized.
 * @param z2 The target vector z value, which should be normalized.
 * @return This quaternion for chaining */
public Quaternion setFromCross (final float x1, final float y1, final float z1, final float x2, final float y2, final float z2) {
  final float dot = MathUtils.clamp(Vector3.dot(x1, y1, z1, x2, y2, z2), -1f, 1f);
  final float angle = (float)Math.acos(dot);
  return setFromAxisRad(y1 * z2 - z1 * y2, z1 * x2 - x1 * z2, x1 * y2 - y1 * x2, angle);
}

代码示例来源：origin: libgdx/libgdx

/** Set this quaternion to the rotation between two vectors.
 * @param x1 The base vectors x value, which should be normalized.
 * @param y1 The base vectors y value, which should be normalized.
 * @param z1 The base vectors z value, which should be normalized.
 * @param x2 The target vector x value, which should be normalized.
 * @param y2 The target vector y value, which should be normalized.
 * @param z2 The target vector z value, which should be normalized.
 * @return This quaternion for chaining */
public Quaternion setFromCross (final float x1, final float y1, final float z1, final float x2, final float y2, final float z2) {
  final float dot = MathUtils.clamp(Vector3.dot(x1, y1, z1, x2, y2, z2), -1f, 1f);
  final float angle = (float)Math.acos(dot);
  return setFromAxisRad(y1 * z2 - z1 * y2, z1 * x2 - x1 * z2, x1 * y2 - y1 * x2, angle);
}

代码示例来源：origin: libgdx/libgdx

/** Spherically interpolates between this vector and the target vector by alpha which is in the range [0,1]. The result is
 * stored in this vector.
 *
 * @param target The target vector
 * @param alpha The interpolation coefficient
 * @return This vector for chaining. */
public Vector3 slerp (final Vector3 target, float alpha) {
  final float dot = dot(target);
  // If the inputs are too close for comfort, simply linearly interpolate.
  if (dot > 0.9995 || dot < -0.9995) return lerp(target, alpha);
  // theta0 = angle between input vectors
  final float theta0 = (float)Math.acos(dot);
  // theta = angle between this vector and result
  final float theta = theta0 * alpha;
  final float st = (float)Math.sin(theta);
  final float tx = target.x - x * dot;
  final float ty = target.y - y * dot;
  final float tz = target.z - z * dot;
  final float l2 = tx * tx + ty * ty + tz * tz;
  final float dl = st * ((l2 < 0.0001f) ? 1f : 1f / (float)Math.sqrt(l2));
  return scl((float)Math.cos(theta)).add(tx * dl, ty * dl, tz * dl).nor();
}

代码示例来源：origin: libgdx/libgdx

/** Spherically interpolates between this vector and the target vector by alpha which is in the range [0,1]. The result is
 * stored in this vector.
 *
 * @param target The target vector
 * @param alpha The interpolation coefficient
 * @return This vector for chaining. */
public Vector3 slerp (final Vector3 target, float alpha) {
  final float dot = dot(target);
  // If the inputs are too close for comfort, simply linearly interpolate.
  if (dot > 0.9995 || dot < -0.9995) return lerp(target, alpha);
  // theta0 = angle between input vectors
  final float theta0 = (float)Math.acos(dot);
  // theta = angle between this vector and result
  final float theta = theta0 * alpha;
  final float st = (float)Math.sin(theta);
  final float tx = target.x - x * dot;
  final float ty = target.y - y * dot;
  final float tz = target.z - z * dot;
  final float l2 = tx * tx + ty * ty + tz * tz;
  final float dl = st * ((l2 < 0.0001f) ? 1f : 1f / (float)Math.sqrt(l2));
  return scl((float)Math.cos(theta)).add(tx * dl, ty * dl, tz * dl).nor();
}

代码示例来源：origin: neo4j/neo4j

public static DoubleValue acos( AnyValue in )
{
  if ( in instanceof NumberValue )
  {
    return doubleValue( Math.acos( ((NumberValue) in).doubleValue() ) );
  }
  else
  {
    throw needsNumbers( "acos()" );
  }
}

代码示例来源：origin: prestodb/presto

@Test
public void testAcos()
{
  for (double doubleValue : DOUBLE_VALUES) {
    assertFunction("acos(" + doubleValue + ")", DOUBLE, Math.acos(doubleValue));
    assertFunction("acos(REAL '" + (float) doubleValue + "')", DOUBLE, Math.acos((float) doubleValue));
  }
  assertFunction("acos(NULL)", DOUBLE, null);
}

代码示例来源：origin: prestodb/presto

@Description("arc cosine")
@ScalarFunction
@SqlType(StandardTypes.DOUBLE)
public static double acos(@SqlType(StandardTypes.DOUBLE) double num)
{
  return Math.acos(num);
}