Automatic generation produced by ISE Eiffel
note description: "[ This is the Barnes and Hut implementation for the n_body_force_solver of a particle system. The runtime is O (n log n) where n is the number of particles. The method was first proposed in: "A Hierarchical O(n log n) force calculation algorithm", J. Barnes and P. Hut, Nature, v. 324 (1986) To calculate the force on a_particle an EG_QUAD_TREE (node) is traversed where force is either traverse (node): 1. if node is a leaf force := n_body_force (a_particle, node.particle) 2. size of node region / distance between a_particle and center of mass of node < theta force := n_body_force (a_particle, node.center_of_mass_particle) 3. none of the above for all children c of node force := force + traverse (c) The larger theta the better the runtime but also the higher the error since center_of_mass_particle is only an approximation of all the particle in the children of node. ]" legal: "See notice at end of class." status: "See notice at end of class." author: "Benno Baumgartner" date: "$Date: 2017-01-05 08:52:29 -0900 (Thu, 05 Jan 2017) $" revision: "$Revision: 99702 $" deferred class interface EG_PARTICLE_SIMULATION_BH [G -> NUMERIC] feature -- Access arc_cosine (v: REAL_64): REAL_64 -- Trigonometric arccosine of radian v -- in the range [0, pi]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class arc_sine (v: REAL_64): REAL_64 -- Trigonometric arcsine of radian v -- in the range [-pi/2, +pi/2]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class arc_tangent (v: REAL_64): REAL_64 -- Trigonometric arctangent of radian v -- in the range [-pi/2, +pi/2]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class ceiling (v: REAL_64): REAL_64 -- Least integral greater than or equal to v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class cosine (v: REAL_64): REAL_64 -- Trigonometric cosine of radian v approximated -- in the range [-pi/4, +pi/4]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class dabs (v: REAL_64): REAL_64 -- Absolute of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class Euler: REAL_64 = 2.7182818284590452353602874713526625 -- Logarithm base -- (from MATH_CONST) exp (x: REAL_64): REAL_64 -- Exponential of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class floor (v: REAL_64): REAL_64 -- Greatest integral less than or equal to v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class force (a_particle: like particle_type): G -- The force affecting a_particle. -- (from EG_PARTICLE_SIMULATION) ensure -- from EG_PARTICLE_SIMULATION result_exists: Result /= Void generating_type: TYPE [detachable EG_PARTICLE_SIMULATION_BH [G]] -- Type of current object -- (type of which it is a direct instance) -- (from ANY) ensure -- from ANY generating_type_not_void: Result /= Void generator: STRING_8 -- Name of current object's generating class -- (base class of the type of which it is a direct instance) -- (from ANY) ensure -- from ANY generator_not_void: Result /= Void generator_not_empty: not Result.is_empty last_theta_average: REAL_64 -- The average theta value on last call to `force`. log (v: REAL_64): REAL_64 -- Natural logarithm of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class log10 (v: REAL_64): REAL_64 -- Base 10 logarithm of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class log_2 (v: REAL_64): REAL_64 -- Base 2 logarithm of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class particles: LIST [like particle_type] -- Particles in the system. -- (from EG_PARTICLE_SIMULATION) Pi: REAL_64 = 3.1415926535897932384626433832795029 -- (from MATH_CONST) Pi_2: REAL_64 = 1.5707963267948966192313216916397514 -- (from MATH_CONST) Pi_4: REAL_64 = 0.7853981633974483096156608458198757 -- (from MATH_CONST) quad_tree: detachable EG_QUAD_TREE -- The quad tree to traverse. sine (v: REAL_64): REAL_64 -- Trigonometric sine of radian v approximated -- in range [-pi/4, +pi/4]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class sqrt (v: REAL_64): REAL_64 -- Square root of v. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class Sqrt2: REAL_64 = 1.4142135623730950488016887242096981 -- Square root of 2 -- (from MATH_CONST) tangent (v: REAL_64): REAL_64 -- Trigonometric tangent of radian v approximated -- in range [-pi/4, +pi/4]. -- (from DOUBLE_MATH) ensure -- from DOUBLE_MATH instance_free: class theta: REAL_64 -- The higher theta the more approximations are made (see comment in indexing) feature -- Comparison frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void -- or attached to isomorphic object structures? -- (from ANY) ensure -- from ANY instance_free: class shallow_implies_deep: standard_equal (a, b) implies Result both_or_none_void: (a = Void) implies (Result = (b = Void)) same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b)) symmetric: Result implies deep_equal (b, a) frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void or attached -- to objects considered equal? -- (from ANY) ensure -- from ANY instance_free: class definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b)) frozen is_deep_equal alias "≡≡≡" (other: EG_PARTICLE_SIMULATION_BH [G]): BOOLEAN -- Are Current and other attached to isomorphic object structures? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY shallow_implies_deep: standard_is_equal (other) implies Result same_type: Result implies same_type (other) symmetric: Result implies other.is_deep_equal (Current) is_equal (other: EG_PARTICLE_SIMULATION_BH [G]): BOOLEAN -- Is other attached to an object considered -- equal to current object? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY symmetric: Result implies other ~ Current consistent: standard_is_equal (other) implies Result frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void or attached to -- field-by-field identical objects of the same type? -- Always uses default object comparison criterion. -- (from ANY) ensure -- from ANY instance_free: class definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b)) frozen standard_is_equal alias "≜" (other: EG_PARTICLE_SIMULATION_BH [G]): BOOLEAN -- Is other attached to an object of the same type -- as current object, and field-by-field identical to it? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY same_type: Result implies same_type (other) symmetric: Result implies other.standard_is_equal (Current) feature -- Status report conforms_to (other: ANY): BOOLEAN -- Does type of current object conform to type -- of other (as per Eiffel: The Language, chapter 13)? -- (from ANY) require -- from ANY other_not_void: other /= Void same_type (other: ANY): BOOLEAN -- Is type of current object identical to type of other? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY definition: Result = (conforms_to (other) and other.conforms_to (Current)) feature -- Duplication copy (other: EG_PARTICLE_SIMULATION_BH [G]) -- Update current object using fields of object attached -- to other, so as to yield equal objects. -- (from ANY) require -- from ANY other_not_void: other /= Void type_identity: same_type (other) ensure -- from ANY is_equal: Current ~ other frozen deep_copy (other: EG_PARTICLE_SIMULATION_BH [G]) -- Effect equivalent to that of: -- `copy` (other . `deep_twin`) -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY deep_equal: deep_equal (Current, other) frozen deep_twin: EG_PARTICLE_SIMULATION_BH [G] -- New object structure recursively duplicated from Current. -- (from ANY) ensure -- from ANY deep_twin_not_void: Result /= Void deep_equal: deep_equal (Current, Result) frozen standard_copy (other: EG_PARTICLE_SIMULATION_BH [G]) -- Copy every field of other onto corresponding field -- of current object. -- (from ANY) require -- from ANY other_not_void: other /= Void type_identity: same_type (other) ensure -- from ANY is_standard_equal: standard_is_equal (other) frozen standard_twin: EG_PARTICLE_SIMULATION_BH [G] -- New object field-by-field identical to other. -- Always uses default copying semantics. -- (from ANY) ensure -- from ANY standard_twin_not_void: Result /= Void equal: standard_equal (Result, Current) frozen twin: EG_PARTICLE_SIMULATION_BH [G] -- New object equal to Current -- `twin` calls `copy`; to change copying/twinning semantics, redefine `copy`. -- (from ANY) ensure -- from ANY twin_not_void: Result /= Void is_equal: Result ~ Current feature -- Basic operations frozen default: detachable EG_PARTICLE_SIMULATION_BH [G] -- Default value of object's type -- (from ANY) frozen default_pointer: POINTER -- Default value of type POINTER -- (Avoid the need to write p.`default` for -- some p of type POINTER.) -- (from ANY) ensure -- from ANY instance_free: class default_rescue -- Process exception for routines with no Rescue clause. -- (Default: do nothing.) -- (from ANY) frozen do_nothing -- Execute a null action. -- (from ANY) ensure -- from ANY instance_free: class feature -- Implementation between (n, a, b: REAL_64): BOOLEAN -- Is n a value between a and b? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class delta_x (angle: REAL_64; length: REAL_64): REAL_64 -- Get dx component of line segment with length and angle. -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class delta_y (angle: REAL_64; length: REAL_64): REAL_64 -- Get dy component of line segment with length and angle. -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class distance (x1, y1, x2, y2: REAL_64): REAL_64 -- Calculate distance between (x1, y1) and (x2, y2). -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class distance_from_line (x, y, x1, y1, x2, y2: REAL_64): REAL_64 -- Calculate distance between (x, y) and (x1, y1)-(x2, y2). -- The line is considered to be infinite. -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class line_angle (x1, y1, x2, y2: REAL_64): REAL_64 -- Return angle of line from (x1, y1) to (x2, y2) relative to world. -- clockwise. 0.0 is 3 o'clock. -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class modulo (a, b: REAL_64): REAL_64 -- a modulo b. -- (from EV_MODEL_DOUBLE_MATH) require -- from EV_MODEL_DOUBLE_MATH divisible: b /= 0.0 ensure -- from EV_MODEL_DOUBLE_MATH in_interval: Result >= 0.0 and Result < b instance_free: class point_on_ellipse (x, y, xc, yc, r1, r2: REAL_64): BOOLEAN -- Is (x, y) inside specified ellipse? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH equals_point_on_rotated: Result = point_on_rotated_ellipse (x, y, xc, yc, r1, r2, 0.0) instance_free: class point_on_ellipse_boundary (x, y, xc, yc, r1, r2, width: REAL_64): BOOLEAN -- Is (x, y) on specified ellipse border? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_line (x, y, x1, y1, x2, y2, width: REAL_64): BOOLEAN -- Is (x, y) on line from (x2, y2) to (x1, y1) with width? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_polygon (x, y: REAL_64; points: SPECIAL [EV_COORDINATE]): BOOLEAN -- Is (x, y) contained in polygon with points? -- Based on code by Hanpeter van Vliet. -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_rectangle (x, y, x1, y1, x2, y2: REAL_64): BOOLEAN -- Is (x, y) inside specified box? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_rotated_ellipse (x, y, xc, yc, r1, r2, angle: REAL_64): BOOLEAN -- Is ('x', y) inside specified ellipse? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_rotated_ellipse_boundary (x, y, xc, yc, r1, r2, angle, width: REAL_64): BOOLEAN -- Is (x, y) on specified ellipse border? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class point_on_segment (x, y, x1, y1, x2, y2, width: REAL_64): BOOLEAN -- Is (x, y) on segment [(x2, y2), (x1, y1)] with width? -- (from EV_MODEL_DOUBLE_MATH) ensure -- from EV_MODEL_DOUBLE_MATH instance_free: class feature -- Element change. set_particles (a_particles: like particles) -- Set `particles` to a_particles and build `quad_tree`. require -- from EG_PARTICLE_SIMULATION a_particles_not_void: a_particles /= Void not_empty: not a_particles.is_empty ensure -- from EG_PARTICLE_SIMULATION set: particles = a_particles ensure then quad_tree_exists: quad_tree /= Void set_theta (a_theta: like theta) -- Set `theta` to a_theta. require a_theta_in_range: theta >= 0.to_double and theta <= 1.0 ensure set: theta = a_theta feature -- Output Io: STD_FILES -- Handle to standard file setup -- (from ANY) ensure -- from ANY instance_free: class io_not_void: Result /= Void out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) ensure -- from ANY out_not_void: Result /= Void print (o: detachable ANY) -- Write terse external representation of o -- on standard output. -- (from ANY) ensure -- from ANY instance_free: class frozen tagged_out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) ensure -- from ANY tagged_out_not_void: Result /= Void feature -- Platform Operating_environment: OPERATING_ENVIRONMENT -- Objects available from the operating system -- (from ANY) ensure -- from ANY instance_free: class operating_environment_not_void: Result /= Void invariant quad_tree_exists: quad_tree /= Void -- from EG_PARTICLE_SIMULATION particles_exist: particles /= Void particles_not_empty: not particles.is_empty -- from ANY reflexive_equality: standard_is_equal (Current) reflexive_conformance: conforms_to (Current) note copyright: "Copyright (c) 1984-2016, Eiffel Software and others" license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)" source: "[ Eiffel Software 5949 Hollister Ave., Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Website http://www.eiffel.com Customer support http://support.eiffel.com ]" end -- class EG_PARTICLE_SIMULATION_BH -- Generated by Eiffel Studio --
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